Treating sulfide glass surfaces and making solid state laminate electrode assemblies

ABSTRACT

Methods for making solid-state laminate electrode assemblies include methods of forming a solid electrolyte interphase (SEI) by ion implanting nitrogen and/or phosphorous into the glass surface by ion implantation.

STATEMENT OF GOVERNMENT SUPPORT

This invention was made with Government support under Award No.:DE-AR0000772 awarded by the Advanced Research Projects Agency-Energy(ARPA-E), U.S. Department of Energy. The Government has certain rightsin this invention.

INCORPORATION BY REFERENCE

An Application Data Sheet is filed concurrently with this specificationas part of the present application. Each application that the presentapplication claims benefit of or priority to as identified in theconcurrently filed Application Data Sheet is incorporated by referenceherein in its entirety and for all purposes.

BACKGROUND

There is a continuing need for high performance battery cells, and theirassociated cell components, and particularly for high energy densityrechargeable lithium metal batteries.

SUMMARY

The present disclosure describes methods for making solid-state laminateelectrode assemblies composed of a thin thermally evaporated lithiummetal layer and a Li ion conducting sulfide glass substrate comprising asulfide glass solid electrolyte sheet, including methods for makingpristine lithium metal layers and thin extruded lithium metal foils. Invarious embodiments the thin evaporated lithium metal layer is notgreater than 10 um thick and is deposited in a vacuum directly onto afirst major surface of the sulfide glass substrate (e.g, a sulfide glasssolid electrolyte sheet encapsulated on one or more surfaces by ananofilm). In various embodiments the method for making the solid-statelaminate includes providing a thermal path for removing a sufficientamount of heat away from the sulfide glass substrate to prevent thesulfide glass solid electrolyte sheet (typically 5 to 100 um thick) fromdenitrifying, and preferably the heat removed is sufficient to maintainthe temperature of the sulfide glass substrate to a temperature valuethat is below the glass transition temperature of the sulfide glasssolid electrolyte sheet (T_(g)). In various embodiments the thermal pathcomprises a heat transfer fluid (e.g., a cryogenic fluid such Argon gas)in direct contact with the second major surface of the sulfide glasssubstrate. In particular embodiments, the thermal path is formed bymounting the sulfide glass substrate to a cooling fixture having areceptacle for receiving and holding the glass substrate and therewithforming a volume gap for admitting the Argon gas between the secondmajor surface of the glass and a backplane of the fixture. In variousembodiments the Argon gas is caused to flow through the volume gapduring the thermal evaporating operation. In various embodiments, thetemperature of the sulfide glass substrate during the evaporationoperation is controlled by adjusting the temperature, pressure and flowrate of the Argon gas flowing through the fixture.

In various embodiments a thin thermally evaporated lithium metal layercan also be formed on a current collecting substrate, such as copperfoil, and the exposed surface of the lithium metal layer is protected byforming a thin protective fluid on the surface of the lithium metal. Invarious embodiments the protective fluid is applied to the surface ofthe thin lithium metal layer via a gravure cylinder (e.g., gravureprinting the protective liquid onto the lithium metal surface). Incertain embodiments, the surface of the thin thermally evaporatedlithium metal layer may be treated by ion bombardment to smooth itssurface and remove pits and voids (e.g., using low-energy Argon ionbombardment).

In one aspect the present disclosure provides methods for making asolid-state laminate electrode assembly.

In various embodiments the solid-state laminate electrode assemblycomprises a lithium metal layer reactively bonded to a lithium ionconducting sulfide glass layer. Preferably, the reactive bond issufficiently complete that it forms a continuous solid electrolyteinterphase (SEI) at the boundary between the layers.

In various embodiments, to bring about a continuous SEI, the lithiummetal layer should have a major surface, which, just prior to bonding(e.g., by laminating), is in a highly reactive state (i.e., it issubstantially unpassivated). In various embodiments the method involvesmaking a pristine lithium metal layer having a substantiallyunpassivated first major surface, and therefore highly reactive, andmaintaining the highly reactive surface in its substantiallyunpassivated state until it has been reactively bonded with the sulfideglass layer.

In various embodiments the method comprises:

A method for making a solid-state laminate electrode assembly, themethod comprising the operations of

i) providing a lithium metal laminate structure the laminate comprising:

-   -   a. a lithium metal layer having a first major surface that is        substantially unpassivated; and    -   b. an inert protective material layer that removably covers the        lithium metal first major surface, the protective material layer        in direct contact with the lithium first major surface;

ii) providing an inorganic solid electrolyte laminate structure, thelaminate comprising:

-   -   a. an inorganic lithium ion conducting sulfide glass layer        having a first major surface and an opposing second major        surface; and    -   b. an inert protective material layer that removably covers the        sulfide glass first major surface, the protective material layer        in direct contact with the sulfide glass;

iii) removing the inert protective material layer from the lithium metalfirst major surface;

iv) removing the inert protective material layer off the sulfide glassfirst major surface;

v) reactively bonding the sulfide glass layer with the lithium metallayer via their first major surfaces; and

wherein the reactive bond is complete and the interface between thesulfide glass layer and the lithium metal is defined by a continuoussolid electrolyte interphase.

In various embodiments, the inert protective material layer on thesulfide glass first major surface is a liquid phase layer of a dryhydrocarbon liquid, and the inert protective material layer on thesubstantially unpassivated lithium metal first major surface is a liquidphase layer of a dry hydrocarbon liquid.

In various embodiments, the hydrocarbon liquid on the lithium metalsurface is removed substantially immediately prior to the reactivebonding operation, and optionally the hydrocarbon liquid on the sulfideglass is removed substantially immediately prior to reactively bondingoperation.

In various embodiments, the removal of the hydrocarbon liquid isaccelerated by the application of one or more heat (conductive orconvective), vacuum suction, blowing a jet of dry Ar or He, and blowinga jet of high vapor pressure protective liquid followed by vacuumsuction.

In various embodiments, the operation of cleaning the first majorsurface of the sulfide glass layer under an inert plasma (e.g., Argonplasma), by ion etching; wherein the cleaning operation is performedafter the liquid phase layer of protective fluid has been removed.

In various embodiments, the operation of treating the clean first majorsurface of the sulfide glass under a Nitrogen containing plasma, whereinthe treatment modifies the surface composition of the sulfide glass byintroducing Nitrogen into/onto the glass surface.

In various embodiments, the operation of treating the clean sulfideglass first major surface to form a precursor film consisting of 1 to 5monolayers of a halogen (e.g., iodine) or an interhalogen, or nitrogenonto the clean glass surface, wherein the monolayer(s) react withlithium on bonding to form a solid electrolyte interphase.

In various embodiments, the operation of treating the clean sulfideglass first major surface to form a precursor film of Nitrogen moleculeson the glass surface.

In various embodiments, the solid electrolyte interphase comprises Li₃N.

In various embodiments, a method of making a lithium metal layer havinga substantially unpassivated first major surface, and preferably apristine surface, includes extruding lithium metal directly into aliquid phase of protective fluid (e.g., super dry liquid hydrocarbon).

In various embodiments, a method of making a lithium metal layer havinga substantially unpassivated first major surface, and preferably apristine surface, includes extruding lithium metal and substantiallyimmediately covering the freshly formed lithium metal surfaces with aliquid phase protective fluid.

In various embodiments, the extrusion comprises at least two extrusionsperformed by roll reduction, and the as-extruded lithium metal layersare substantially immediately covered in liquid phase protective fluidright after each roll reduction operation, and maintained under liquidphase protective fluid throughout the process.

In various embodiments, the extrusion comprises purifying a stock oflithium metal to remove non-metallic impurities so that theconcentration of nitrogen in the purified lithium stock is not greaterthan 500 ppm, and extruding the purified lithium metal stock to form alithium metal foil having a first and second major surface and thicknessless than 50 um.

In various embodiments, the lithium metal layer is in the form of a longcontinuous roll, and the method further comprises the operation ofplacing the lithium metal roll into a hermetic canister filled withliquid phase protective fluid, the lithium metal layer completelyimmersed within the protective fluid.

In various embodiments, the substantially unpassivated first majorsurface of the lithium metal layer has never been in direct touchingcontact with a gas phase atmosphere or vacuum.

In various embodiments, a lithium metal laminate structure is provided.The laminate includes:

-   -   i) a lithium metal layer having a first and second major        surface, wherein the first major surface is substantially        unpassivated; and    -   ii) a protective material layer that removably covers and        protects the lithium first major surface in direct contact.

In various embodiments, the substantially unpassivated lithium metalsurface is stable.

In various embodiments, the protective material layer is a liquid phasehydrocarbon liquid, preferably super dry.

In various embodiments, a lithium metal laminate structure is formed viathermal evaporation of lithium metal onto a substrate, and thensubstantially immediately covering the fresh formed lithium metal layerwith a protective material layer (e.g., a liquid phase hyrdrocarbonliquid). In some embodiments the substrate on which the lithium metallayer is formed is copper foil. In other embodiments the substrate maybe a metallized polymeric film (e.g., a PET film metallized with Cu, Nior the like). In a particular embodiment the liquid phase hydrocarbon isapplied onto the first major surface of the evaporated lithium metallayer by gravure printing the hydrocarbon liquid (i.e., via a gravurecylinder).

In various embodiments, to achieve smooth lithium surface the evaporatedlithium metal layer may be treated by ion bombarding its surface (e.g.,using low-energy Argon ion bombardment). For instance, the thermalevaporator may be equipped with an ion gun that generates ions withenergies of a few keV. The ion bombardment may be applied duringevaporation of the lithium metal, or exclusively after the lithium metallayer has formed. The process is generally referred to as ion-beamassisted deposition (IBAD). In this instance, the ion bombardment is aprocess that takes place after the lithium metal layer has formed. IBADis a process known for making optical quality mirrors, and is appliedhere for making a high quality and smooth lithium metal surface. Onceevaporated and optionally smoothed by ion bombardment, the lithium metalsurface is substantially immediately covered in protective fluid, thusforming a lithium metal laminate structure of the present disclosure.The protective fluid may be applied inside the vacuum chamber of theevaporator (and while under vacuum), or it may be applied in a dry boxthat is configured to receive the evaporated lithium metal layer. Invarious embodiments the layer of protective fluid is applied to thelithium metal surface using a gravure printing process, as described inmore detail herein below.

When the lithium metal layer is formed by evaporation (e.g., thermalevaporation) its thickness is generally not greater than 10 um, and moretypically not greater than 5 um (e.g., it is about 5 um, or about 4 um,or about 3 um, or about 2 um, or about 1 um). In some embodiments thethickness of the evaporated lithium metal layer is ultra-thin, e.g.,less than 1 um (e.g., about 100 nm, or about 200 nm, or about 300 nm, orabout 400 nm or about 500 nm) thick. As described in more detail hereinbelow, once the evaporated lithium metal layer is encapsulated by theprotective liquid layer, it may be rolled or otherwise covered with asolid material release layer to form a lithium metal laminate structurehaving a wet-decal architecture as described in detail herein below.

In various embodiments the solid-state laminate electrode assembly ofthe present disclosure is formed by depositing lithium metal onto afreestanding (or freestandable) sulfide solid electrolyte glass layer(e.g., a sulfide glass sheet) or directly onto a nanofilm-encapsulatedsulfide glass solid electrolyte sheet (as described herein below) usinga physical vapor deposition technique such as evaporation or sputtering(e.g., thermal evaporation), the sulfide glass sheet (e.g.,nanofilm-encapsulated) serves as the substrate for lithium deposition).

When referring to the sulfide glass sheet as “freestanding” or“freestandable” it is meant that the sheet is a self-supporting layerthat displays a mechanical strength (e.g., tensile strength) sufficientto allow it (the sheet) to remain intact in the absence of a substrate(i.e., self-supporting), and thereby the freestanding solid electrolytesheet is not dependent upon another self-supporting layer for itscontinuous intact existence (e.g., a positive or negative electrodelayer or an inert carrier film). Accordingly, in various embodiments theinstant freestanding solid electrolyte sulfide glass sheet is“substrate-less.”

In some embodiments it is contemplated that the lithium metal layer maybe thermally evaporated directly onto the glass first major surface, ora precursor film (as described above and below) may be applied to theglass first major surface, and the lithium metal layer deposited ontothe precursor film to form an engineered solid electrolyte interphase(SEI) having improved electrochemical properties.

When thermally evaporating the lithium metal layer onto the freestandingsulfide glass sheet (e.g., a nanofilm-encapsulated glass sheet, asdescribed herein below), care is to be taken to ensure that the sulfideglass does not devitrify and the sheet's first major surface is notdamaged by the evaporation (e.g., thermally damaged). In variousembodiments the sulfide glass substrate sheet (e.g.,nanofilm-encapsulated) is actively cooled during thermal evaporation oflithium metal. Preferably, the temperature of the sulfide glass sheet isat a temperature of 100° C. or less during the evaporation process. By“actively cooled” it is meant that the sulfide glass sheet is cooledwhile the evaporation of lithium metal is taking place. In variousembodiments the substrate (i.e., the sulfide glass sheet) is positionedin a material frame (e.g., a ceramic frame) and while lithium metal iscoated onto the first major surface (or precursor film), the opposingsecond major surface is actively cooled (e.g., by flowing a cool inertgas in direct contact with the second major surface). Typically the coolinert gas is cold Argon, and preferably obtained from a cryogenic Argontank. For instance, the inert gas (e.g., cool Argon gas) contacts thesulfide glass second major surface and it (the gas) is applied to thesurface at a temperature that is no greater than 10° C., or no greaterthan 0° C., or no greater than −10° C., or no greater than −20° C. Whenactively cooling the sulfide glass sheet during evaporation, the sheetis preferably release-ably sealed to the ceramic frame in order toprevent the cool Argon gas from releasing into the vacuum chamber of theevaporator or from diffusing into the evaporating lithium flux (e.g.,the edges of the glass sheet glued to the frame, such as with an epoxy).In various embodiments several frames are incorporated into a cassetteof frames, to allow for multiple evaporations in a single run. In otherembodiments the sulfide glass sheet may be passively cooled, which is tomean cooled to a temperature below 15° C. prior to evaporating thelithium metal onto the glass first major surface. Typically whenpassively cooled the sulfide glass sheet is at a temperature that isless than 10° C. prior to evaporation, or less than 0° C., or less than−10° C., or less than −20° C. In some embodiments the substrate is bothactively cooled and passively cooled as described above. In otherembodiments the substrate is exclusively passively cooled (i.e.,passively cooled and not actively cooled), or vice versa exclusivelyactively cooled.

In various embodiments, an inorganic solid electrolyte laminatestructure is provided. The laminate includes:

-   -   i) a lithium ion conducting sulfide glass layer having a first        and second major surface; and    -   ii) a protective material layer that removably covers and        protects the sulfide glass first major surface.

In various embodiments, the protective material layer is a liquid phasehydrocarbon liquid, preferably super dry.

In various embodiments, a method for storing a solid-state laminateelectrode assembly is provided. The method includes making a solid-statelaminate electrode assembly as described herein, and immersing thelaminate electrode assembly into a bath of a liquid phase protectivefluid (e.g., a super dry liquid hydrocarbon).

In various embodiments, a method for storing a lithium metal layerhaving a substantially unpassivated first major surface is provided. Themethod includes making the substantially unpassivated first majorsurface, and immersing the lithium metal layer into a bath of a liquidphase protective fluid (e.g., a super dry liquid hydrocarbon).

In various embodiments, a method for storing a sulfide glass layerhaving a clean first major surface is provided. The method includescleaning the first major surface in an Argon plasma, and immersing thesulfide glass layer into a bath of a liquid phase protective fluid(e.g., a super dry liquid hydrocarbon)

In another aspect the present disclosure provides nanofilm-encapsulatedsulfide based solid electrolyte structures that are resistant tochemical degradation by atmospheric moisture. In accordance with thepresent disclosure, the moisture resistant solid electrolyte structuresare composed of a moisture sensitive and dense inorganic lithium ionconducting sulfide solid electrolyte layer (e.g., a lithium ionconducting sulfide glass sheet) encapsulated on all, or some, of itssurfaces by a continuous inorganic nanofilm that is dense, pinhole freeand conforms to the glass surfaces of the sulfide sheet, and thereonprovides a moisture barrier that protects the encapsulated surfaces fromreacting with ambient moisture during storage or manufacture.

In various embodiments the moisture barrier provided by the continuousnanofilm is sufficiently water impervious to prevent egress of hydrogensulfide gas during manufacture in a controlled atmosphere dry box or dryroom (e.g., the atmosphere having a dew point of −20° C. or lower, or−40° C. or lower, or −60° C. or lower). In various embodiments, thenanofilm is configured as a moisture barrier and does not impart a largearea specific resistance (ASR); e.g., the ASR of the nanoencapsulatedsulfide glass solid electrolyte sheet is less than 200 Ω-cm², whenmeasured in a battery cell at room temperature; and preferably less than100 Ω-cm², and even more preferably less than 50 Ω-cm².

In various embodiments, the nanofilm-encapsulation is configured toimpart water imperviousness and to enhance mechanical strength. Forinstance, in various embodiments the nanofilm-encapsulation increasesthe flexural strength of the sulfide glass sheet by greater than 30%,preferably greater than 50%, and even more preferably greater than 100%.

In various embodiments the nanofilm-encapsulated sulfide glass sheet, asdescribed herein, and in the claims, is, itself, a discrete battery cellseparator component, and thus not yet disposed in a battery cell orcombined with an electroactive material layer (e.g., when forming asolid-state laminate electrode assembly). For instance, the discretenanofilm-encapsulated sulfide glass sheet may be in the form of acontinuous web, and optionally wound and disposed for storage and/ormanufacture as a roll of battery separator.

In various embodiments, the nanofilm-encapsulated sulfide glass solidelectrolyte sheet is made by depositing onto the sulfide glass sheet acontinuous inorganic nanofilm that encapsulates, in direct contact, thefirst and second major opposing surfaces of the sulfide sheet, as wellas one or more peripheral edge surfaces. In some embodiments, when thesulfide sheet is of a substantially rectangular shape, the continuousinorganic nanofilm is configured to encapsulate, in direct contact, themajor opposing surfaces of the sulfide glass sheet, and the opposinglengthwise edge surfaces, but not necessarily the opposing widthwiseedge surfaces. In other embodiments the sulfide glass sheet is fullyencapsulated on all surfaces by the inorganic nanofilm, including allperipheral edge surfaces (lengthwise and widthwise edge surfaces).

In various embodiments, the continuous and conformal nanofilm is acontinuous inorganic nanolayer having a substantially uniformcomposition and thickness as a function of its position on the surfaceof the glass sheet.

In various embodiments the continuous nanofilm is composed of two ormore continuous inorganic nanolayers, which are configured, relative toeach other and the surface of the sulfide glass sheet, to provide amoisture barrier and one or more performance advantages, includingenhanced mechanical strength (e.g., a 30% increase in flexuralstrength), reduced interface resistance in contact with lithium metal,and/or improved chemical resistance to liquid electrolytes (e.g., theencapsulation leading to zero dissolution of sulfur), and/or oxidativestability in direct contact with electroactive cathode materials.

In various embodiments the encapsulating nanofilm is formed onto thesulfide glass sheet by a technique known as atomic layer deposition(ALD), and to a thickness that is typically less than 100 nm (e.g.,about 1 nm or less, or about 2 nm, or about 5 nm, or about 10 nm, orabout 20 nm, or about 30 nm, or about 40 nm, or about 50 nm, or about 60nm, or about 70 nm, or about 80 nm, or about 90 nm, or about 100 nm). Invarious embodiments, the surfaces of the sulfide glass sheet are cleanedby ion etching (e.g., in Argon plasma) prior to ALD deposition of thenanofilm,

In another aspect the present disclosure provides a solid-state laminateelectrode assembly composed of the nano-encapsulated sulfide glass sheetstructure, as described above, and a lithium metal layer on a firstmajor surface of the sulfide glass sheet. The lithium metal layer is indirect intimate contact with the encapsulating nanofilm.

In various embodiments the lithium metal layer may be deposited onto thefirst major surface of the nano-encapsulated sulfide glass sheet bythermal evaporation of lithium metal directly onto the nanofilm. Inother embodiments the lithium metal layer may be laminated to the firstmajor surface of the encapsulated sulfide glass sheet structure, indirect contact with the surface of the nanofilm. When thermallyevaporated the thickness of the lithium metal layer is generally notgreater than 10 um, and more typically not greater than 5 um.

In another aspect, the present disclosure provides a battery cell thatincorporates the nanofilm-encapsulated sulfide glass solid electrolytestructure as a solid electrolyte separator

In various embodiments the material composition of the nanofilm ornanolayer is an insulator in bulk form, but is transparent or permeableto lithium ions as a nano layer.

In another aspect, the present disclosure provides methods for makingsolid-state laminate electrode assemblies include methods of forming asolid electrolyte interphase (SEI) by ion implanting nitrogen and/orphosphorous into the glass surface by ion implantation.

In various embodiments such a method for making a solid-state laminateelectrode assembly includes the operations of providing a lithium ionconducting sulfide glass substrate, the substrate comprising a sulfideglass solid electrolyte sheet having room temperature Li ionconductivity of at least 10⁻⁵ S/cm, the sulfide glass substrate havingfirst and second major surfaces; injecting nitrogen and/or phosphorousinto the first surface of the sulfide glass substrate, wherein thenitrogen and/or phosphorous penetrates the glass surface forming animplanted zone; and, evaporating lithium metal onto the implanted zoneof the sulfide glass substrate; wherein at least a portion of theevaporated lithium reacts with the injected nitrogen and/or phosphorousto form a solid electrolyte interphase (SEI) layer comprising lithiumand one or both of nitrogen and phosphorous.

These and other aspects of the present disclosure are described infurther detail below, including with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow diagram for making a solid-state laminateelectrode assembly in accordance with one embodiments of the presentdisclosure.

FIGS. 2A-D illustrate cross sectional depictions of standalone alkalimetal laminate structures in accordance with various embodiments of thepresent disclosure.

FIGS. 2E-H illustrate cross sectional depictions of standalone inorganicsolid electrolyte laminate structures in accordance with variousembodiments of the present disclosure.

FIGS. 2I-P illustrate cross sectional depictions ofnanofilm-encapsulated sulfide glass separator sheets in accordance withvarious embodiments of the present disclosure.

FIG. 2Q is a process flow diagram illustrating various processembodiments of making a nanofilm-encapsulated sulfide glass solidelectrolyte structure in accordance with the present disclosure.

FIGS. 3A-E illustrate cross sectional and top down depictions of lithiummetal layers and lithium metal surfaces.

FIGS. 4A-G illustrate apparatus and method for making a lithium metallayer having substantially unpassivated surfaces, in accordance withvarious embodiments of the present disclosure.

FIGS. 4H-J illustrate apparatus, methods and tools for making a lithiummetal layer by evaporation and having substantially unpassivatedsurfaces, in accordance with various embodiments of the presentdisclosure.

FIG. 4K illustrates apparatus and process for making vacuum die extrudedlithium metal layers in accordance with an embodiment of the presentdisclosure.

FIGS. 5A-B illustrate a lithium roll assembly cartridge according to oneembodiment of the present disclosure.

FIG. 6A illustrates an apparatus and method for cleaning and treating aninorganic solid electrolyte layer, in accordance with an embodiment ofthe present disclosure.

FIG. 6B illustrates a cross sectional depiction of an inorganic solidelectrolyte layer coated with a thin precursor film, in accordance withone embodiment of the present disclosure.

FIG. 7 illustrates a cross sectional depiction of a solid-state laminateelectrode assembly in accordance with one embodiment of the presentdisclosure.

FIG. 8A illustrates an apparatus and method for making a solid-statelaminate electrode assembly in accordance with one embodiment of thepresent disclosure.

FIG. 8B-C illustrates apparatus, method and tool for making asolid-state laminate electrode assembly in accordance with oneembodiment of the present disclosure.

FIGS. 8D illustrates cross sectional depictions of solid-state laminateelectrode assemblies in accordance with one embodiment of the presentdisclosure.

FIG. 8E illustrates an arrangement of a combination apparatus (or tool)suitable for thin film fabrication methods described herein, includingALD tool, a lithium thermal evaporation tool, and an Argon plasma ionetch tool for cleaning sulfide glass surfaces.

FIG. 8F is a process flow diagram illustrating methods for makingsolid-state laminate electrode assemblies in accordance with embodimentsof the present disclosure.

FIG. 9 illustrates a roll assembly cartridge containing a solid-statelaminate electrode assembly according to one embodiment of the presentdisclosure.

FIG. 10 illustrates a cross sectional depiction of a battery cell inaccordance with one embodiment of the present disclosure.

FIG. 11 illustrates a cross sectional depiction of a battery cell inaccordance with one embodiment of the present disclosure.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Reference will now be made in detail to specific embodiments of thisdisclosure. Examples of the specific embodiments are illustrated in theaccompanying drawings. While this disclosure will be described inconjunction with these specific embodiments, it will be understood thatit is not intended to limit this disclosure to such specificembodiments. On the contrary, it is intended to cover alternatives,modifications, and equivalents as may be included within the spirit andscope of this disclosure. In the following description, numerousspecific details are set forth in order to provide a thoroughunderstanding of this disclosure. This disclosure may be practicedwithout some or all of these specific details. In other instances, wellknown process operations have not been described in detail in order tonot unnecessarily obscure this disclosure.

Introduction

The present disclosure describes solid-state laminate electrodeassemblies and various methods for making the solid-state laminateelectrode assemblies.

In various embodiments the solid-state laminate electrode assemblycomprises a lithium metal layer reactively bonded to a lithium ionconducting sulfide glass layer. Preferably, the reactive bond issufficiently complete that it forms a continuous solid electrolyteinterphase (SEI) at the boundary between the layers.

In various embodiments, to bring about a continuous SEI, the lithiummetal layer should have a major surface, which, just prior to bonding(e.g., by laminating), is in a highly reactive state (i.e., it issubstantially unpassivated). In various embodiments the method involvesmaking a pristine lithium metal layer having a substantiallyunpassivated first major surface, and therefore highly reactive, andmaintaining the highly reactive surface in its substantiallyunpassivated state until it has been reactively bonded with the sulfideglass layer.

In various embodiments, the present disclosure provides methods formaking a solid-state laminate electrode assembly. Such a methodincludes:

-   -   ii) providing a lithium metal laminate structure the laminate        comprising:        -   a. a lithium metal layer having a first major surface that            is substantially unpassivated; and        -   b. an inert protective material layer that removably covers            the lithium metal first major surface, the protective            material layer in direct contact with the lithium first            major surface;    -   ii) providing an inorganic solid electrolyte laminate structure,        the laminate comprising:        -   c. an inorganic lithium ion conducting sulfide glass layer            having a first major surface and an opposing second major            surface; and        -   d. an inert protective material layer that removably covers            the sulfide glass first major surface, the protective            material layer in direct contact with the sulfide glass;    -   iii) removing the inert protective material layer off the        lithium metal first major surface;    -   iv) removing the inert protective material layer off the sulfide        glass first major surface;    -   v) reactively bonding the sulfide glass layer with the lithium        metal layer via their first major surfaces; and    -   wherein the reactive bond is complete and the interface between        the sulfide glass layer and the lithium metal is defined by a        continuous solid electrolyte interphase.

In various embodiments the reactive bonding operation is a laminationprocess performed in a chamber filled with a dry gas (e.g., dry Argon).Typically the laminating operation involves applying both heat andpressure.

In various embodiments the inert protective material layer removablycovering one or both of the sulfide glass first major surface and thesubstantially unpassivated lithium metal surface is a liquid phaseprotective fluid.

In various embodiments the liquid phase protective fluid removablycovering the lithium metal surface is removed just prior to the reactivebonding operation (e.g., the period of time between removing the liquidphase protective fluid and reactive bonding is less than 10 seconds, andpreferably less than 5 seconds, and even more preferably less than 2seconds).

In various embodiments to ensure that the interface formed between thelithium metal layer and the lithium ion conducting sulfide glass iselectrochemically operable or otherwise optimized, an SEI may beengineered by coating a first major surface of the sulfide glass with athin precursor film that reacts with lithium metal during the bondingoperation to form a solid electrolyte interphase.

In some embodiments the sulfide glass surface may be treated under aNitrogen containing plasma to incorporate Nitrogen into the surface ofthe glass, and then forming a lithium nitride.

In various embodiments the method further comprises the operation ofcleaning the first major surface of the sulfide glass under an Argonplasma, by ion etching, this operation performed after removing theinert protective material layer off of the sulfide glass but beforereactive bonding.

In various embodiments the method further comprises the operation oftreating the clean sulfide glass first major surface to modify itssurface composition. In various embodiments the surface composition ismodified by placing the clean first major surface of the sulfide glassunder a Nitrogen containing plasma, wherein the treatment modifies thesurface composition of the sulfide glass by introducing Nitrogeninto/onto the surface.

In various embodiments the method further comprises the operation ofcoating the clean sulfide glass first major surface with a thinprecursor film having a composition that will react in direct contactwith lithium metal.

In various embodiments the thin precursor film is formed by condensingbetween 1 to 5 monolayers of a Halogen (e.g., iodine) or Interhalogen orNitrogen onto the clean sulfide glass surface; wherein the iodinemonolayers leads to reactive wetting during the reactive bondingoperation.

In various embodiments the method further comprises coating the cleansulfide glass surface to form a precursor film that reacts with lithiumduring the reactive bonding operation to form a solid electrolyteinterphase between the lithium metal layer and sulfide glass layer.

In various embodiments the inert protective material layer removablycovering one or both of the sulfide glass first major surface and thesubstantially unpassivated lithium metal surface is a liquid phaseprotective fluid.

In one aspect the present disclosure provides methods for making apristine lithium metal layer having a substantially unpassivated firstmajor surface, as defined herein below. In various embodiments theopposing second major surface of the pristine lithium metal layer isadhered to a current collector (e.g., a copper foil)

In various embodiments the pristine lithium metal layer is in the formof a long continuous roll of lithium that is immersed in liquid phaseprotective fluid for storage and/or downstream processing of batterycells (e.g., the pristine lithium metal layer at least 100 cm inlength).

In various embodiments the method involves making the pristine lithiummetal layer in a protective inert fluid, and maintaining the pristinelithium metal layer in protective fluid (e.g., protective liquid) toprevent directly exposing the surface to the ambient gaseous atmosphere(including dry Argon of a glove box or dry Air of a dry room). Invarious embodiments the protective fluid is an inert liquid or the vaporof an inert liquid (i.e., protective vapor). In various embodiments thelithium metal layer is in the form of a long continuous ribbon (e.g.,more than 50 cm in length).

In various embodiments the method for making the substantiallyunpassivated lithium metal surface includes an extrusion operation thatproduces a fresh substantially unpassivated lithium first major surfaceinside or surrounded by protective fluid (e.g., a protective and superdry liquid hydrocarbon). By use of the term super dry it is meant thatthe amount of moisture in the liquid hydrocarbon is not greater than 0.1ppm. In various embodiments the pristine lithium metal layer and itssubstantially unpassivated surface is extruded directly into liquidphase protective fluid (i.e., protective liquid), and then optionallythe method further includes winding the lithium metal layer into a longcontinuous roll while it is immersed in liquid phase protective fluid.

In various embodiments the extrusion operation is die extrusion oflithium ingot directly into a super dry liquid hydrocarbon bath. Invarious embodiments the extrusion operation is a roller extrusionwherein the lithium metal foil thickness is roll reduced in protectiveliquid, and in the process forms fresh lithium substantiallyunpassivated lithium metal surfaces, wherein the area of the freshsurfaces so formed is proportional to the reduction in thickness of thelithium layer. In various embodiments multiple roll reduction operationsare performed (e.g., 2, 3, 4 or 5 or more) in order to produce thedesired thickness and to perfect the substantially unpassivated surface(e.g., a pristine surface). In various embodiments, the stock foil usedfor the roll reduction process has been pre-passivated, to improvereproducibility of the starting surface condition. In a particularembodiment a lithium ingot is die extruded directly into protectivefluid to form a pristine lithium metal layer, and then that layer isimmediately roll reduced in protective fluid to the desired thickness,and throughout the process the substantially unpassivated lithium metalsurface remains covered or immersed in liquid phase protective fluid.The pristine lithium metal as formed may then be wound into a longcontinuous roll of pristine lithium metal, the winding performed inprotective fluid (e.g., the winding performed inside liquid phaseprotective fluid).

In various embodiments the substantially unpassivated lithium metalsurfaces are stored in a canister of protective liquid, or they areformed and immediately transferred into the canister, without exposingthe surfaces to the ambient gaseous environment.

In another aspect the present disclosure provides a standaloneelectrochemical material laminate structure for maintaining a majorsurface of a battery active material layer in a substantiallyunpassivated and/or substantially uncontaminated condition duringhandling, storage and/or battery cell fabrication.

In various embodiments the battery active material layer reacts withwater and/or Oxygen, and even under fairly dry ambient conditions, suchas that of a dry air room or a dry Argon filled glove box the batterymaterial surfaces chemically degrade or passivate rather quickly. Thelaminate structures of the present disclosure protect the batterymaterial surfaces by encapsulating them underneath an inert removablelayer, which inhibits moisture and/or oxygen from reaching the surfaces.

Accordingly, the standalone electrochemical material laminate structuresof the present disclosure are particularly useful for making, storingand transporting moisture sensitive battery active material layers, andfor making downstream battery cells and laminate electrode assembliesfrom those material layers.

In accordance with the present disclosure, a standalone electrochemicalmaterial laminate structure may be composed of two or more continuousmaterial layers, wherein at least one of the material layers (i.e., afirst material layer) is a “battery active solid material” having aclean (i.e., substantially uncontaminated) and/or substantiallyunpassivated surface, and another material layer (i.e., a secondmaterial layer) is a “protective material” that is inert, not batteryactive, and removably covers, in direct contact, a first major surfaceof the battery active material.

When referring to a material as “battery active” it generally means thatthe material is active in an electrochemical sense and useful in abattery cell (i.e., it is either an electro-active material or anelectrolyte material). As used herein, the term “battery active solidmaterial layer” means either a solid alkali metal or an inorganic solidelectrolyte having utility as a continuous solid layer in a battery cell(e.g., a lithium metal layer or a Li-ion conducting sulfide glass sheet,respectively).

In contrast to the battery active material layer, the protectivematerial layer is inert and not battery active. By use of the term“inert” it means that the referenced inert material does not chemicallyreact in contact with the battery active solid material on which it isintended to protect. And when referring to the protective material layeras “not battery active,” it is meant that the material layer is notuseful in a battery cell, and is furthermore not intended for use in abattery cell, and not active in a battery/electrochemical sense (i.e.,not an electroactive material or alkali metal ion conductor).

In accordance with the present disclosure the protective material layer:i) provides an encapsulating barrier against direct touching exposurebetween the first major surface of the battery active material layer andthe ambient gaseous atmosphere or contaminants in a vacuum chamber aboutthe layer; ii) is inert in direct contact with the first major surface;and iii) is readily removed without physically damaging the surface. Toachieve these objectives, in various embodiments the protective materiallayer is an inert liquid (e.g., a super dry hydrocarbon liquid) thatencapsulates the surface on which it is applied, and may beevaporatively removed in the absence of solid to solid touching contact

In a first embodiment, the battery active material layer is anelectroactive alkali metal layer having a substantially unpassivatedfirst major surface (e.g., a pristine lithium metal layer), and in suchembodiments the standalone electrochemical material laminate structureis generally referred to herein as a standalone alkali metal laminatestructure; e.g., a standalone lithium metal laminate structure.

In a second embodiment, the battery active material layer is aninorganic solid electrolyte layer having a substantially uncontaminatedfirst major surface (e.g., a lithium ion conducting sulfide glasssheet), and in such embodiments the standalone electrochemical materiallaminate structure is generally referred to herein as a standalone solidelectrolyte laminate structure; e.g., a standalone sulfide glasslaminate structure.

By use of the term “standalone” when referring to an electrochemicalmaterial laminate structure, such as a standalone alkali metal laminatestructure or a standalone solid electrolyte laminate structure, it ismeant to emphasis that the battery active material layer in thestandalone laminate is a discrete battery active material layer that hasnot yet been combined or coupled with a second battery active materiallayer, or yet been placed in a battery cell.

In another aspect the present disclosure provides methods for makinglithium metal layers having substantially unpassivated surfaces andpreventing passivation by encapsulating them with inert liquid. Invarious embodiments the methods include making a lithium metal foilhaving substantially unpassivated surfaces by die extruding a lithiumingot into a bath of super dry liquid hydrocarbons. In variousembodiments the as made substantially unpassivated lithium metal foilmay be further reduced in thickness by roller reduction and applyinghydrocarbon liquid onto the freshly formed surfaces to ensure that theyremain substantially unpassivated. In various embodiments apre-passivated lithium metal layer of thickness (t) may be rollerreduced in a roller mill using multiple roll reduction operations whileat all times maintaining liquid hydrocarbon on the freshly formedlithium metal layer surfaces. By using pre-passivated lithium metal(e.g., passivated by exposure to CO₂), reproducibility is improvedbecause the initial surface condition of the lithium is itselfreproducible, as opposed to using lithium metal that is passivated in aless or uncontrolled fashion. Moreover, the area of freshly formedlithium is proportional to the decrease in thickness of the layer.

In another aspect the present disclosure provides methods for makinginorganic lithium ion conducting sulfide glass sheets havingsubstantially uncontaminated surfaces, and for preventing hydrolysis ofthose surfaces by encapsulating them underneath an inert super dryhydrocarbon fluid (e.g., liquid). For instance, in various embodimentsthe inorganic sulfide glass sheets are cleaned by ion etching in an Arplasma to etch away any contaminated surface(s), and then substantiallyimmediately after the ion etching operation, the cleaned sulfide glasssheet may be immersed in a liquid hydrocarbon bath, or the clean surfaceencapsulated by a protective liquid layer, as described above. Invarious embodiments, the surface composition of the sulfide glass may bemodified during or immediately after cleaning by using an Argon/Nitrogenplasma mixture for incorporating Nitrogen into the surface of thesulfide glass sheet, or the surfaces may be treated sequentially, usinga first ion etch in argon plasma, followed by a second treatment in anitrogen containing plasma (e.g., pure Nitrogen or an Argon/Nitrogenmixture).

In yet another aspect the present disclosure provides methods of makinga strongly adhered fully solid-state inorganic laminate electrodeassembly having a substantially contaminate free inorganic interface. Invarious embodiments the method includes providing a first battery activematerial as a component of a lithium metal laminate structure (e.g., alithium metal layer having a first major surface which is substantiallyunpassivated and protected by an inert hydrocarbon liquid layer);providing a second battery active material layer as a component of aninorganic solid electrolyte laminate structure (e.g., a lithium ionconducting sulfide glass sheet having a clean first major surface thatis devoid of hydrolysis reaction products and protected by an inerthydrocarbon liquid layer); removing the inert hydrocarbon liquid layers;and then, substantially immediately thereafter, reactively bonding thesubstantially unpassivated lithium metal surface to the clean inorganicsulfide glass surface, to form a strongly adhered laminate having aclean inorganic interface with a low area resistance (preferably, lessthan 50 Ω-cm²). Preferably the peel strength of the laminate electrodeassembly is greater than the tensile strength of its lithium metallayer, such that any attempt to peel off the lithium from the laminateresults in the lithium tearing prior to peeling.

In various embodiments, an improved laminate interface is formed bylaminating the fluid protected lithium metal surface to a solidelectrolyte sheet using techniques whereby the fluid is removedsubstantially immediately prior to, or during, the laminating operation,as the solid electrolyte comes into direct contact with the fluid andthe lithium metal layer. In various embodiments, the laminatingoperation effects a three phase boundary of lithium metal layer, solidelectrolyte, and protective fluid, and causes the fluid to be removedfrom the surface substantially instantaneously as the solid electrolytelayer reactively adheres to the pristine lithium metal layer surface.

In another aspect, the present disclosure relates to methods andreagents to form a thin, dense and lithium ion conductive layer betweena lithium metal layer and an inorganic solid electrolyte layer (e.g., alithium ion conducting sulfide glass). The layer is sometimes referredto herein as a solid electrolyte interphase (SEI) as it is formed byreacting a first major surface of the lithium metal layer with a coatingon the glass surface that allows for the glass electrolyte to beoptimized for high ionic conductivity and processability, regardless ofits chemical compatibility with lithium metal.

In another aspect the present disclosure provides methods of makingbattery cells by combining the fully solid-state inorganic laminateelectrode assembly of the present disclosure with a positive electrode(e.g., a lithium ion intercalating positive electrode).

A list of suitable hydrocarbons which may be used as protective fluid(e.g., inert liquid) in accordance with the various embodiments andaspects of the present disclosure is provided below, as well as theirstructural formulas and vapor pressure (and/or boiling point) values. Invarious embodiments, the protective fluid is selected from a group ofsaturated hydrocarbons with the number of carbon atoms from 5 to 15. Inone particular case, the protective fluid is isododecane. The protectivefluids may be a combination of these various fluids. The fluidsgenerally contain no dissolved or dispersed chemicals (e.g., salts,lubricants and/or greases) that would coat the surface of the lithiummetal layer or solid electrolyte layer with a solid film or residue.Accordingly the protective fluid is devoid of any dissolved salts (e.g.,lithium salts).

Suitable protective fluids are chemically inert to Li metal or Li alloysand contain less than 0.1 ppm of moisture, less than 1 ppm of moisture,less than 5 ppm of moisture, less than 10 ppm of moisture. In the casewhen a protective fluid is used in combination with a glass coatingdesigned to form a solid electrolyte interphase (SEI) upon contact withLi, the protective fluid is chosen to be non-reactive with the glasscoating.

Protective Fluids

Saturated Hydrocarbons (Alkanes) C_(n)H_(2n+2)

Straight-Chain Alkanes C₅-C₁₅

-   n-Pentane C₅H₁₂ BP=36° C., Vapor Pressure: 434 mmHg at 20° C.

-   n-Hexane C₆H₁₄ BP=69° C., Vapor Pressure: 121 mmHg at 20° C.

-   n-Heptane C₇H₁₆ BP=99° C., Vapor Pressure: 46 mmHg at 20° C.

-   n-Octane C₈H₁₈ BP=125° C., Vapor Pressure: 11 mmHg at 20° C.

-   n-Nonane C₉H₂₀ BP=151° C., Vapor Pressure: 3.8 mmHg at 25° C.

-   n-Decane C₁₀H₂₂ BP=174° C. Vapor Pressure: 2.7 mmHg at 20° C.

-   n-Undecane C₁₁H₂₄ BP=196° C., Vapor Pressure: 0.4 mmHg at 25° C.

-   n-Dodecane C₁₂H₂₆ BP=216° C., Vapor Pressure: 0.14 mmHg at 25° C.

Branched-Chain Alkanes C₅-C₁₅

-   Isonentane C₅H₁₂ BP=28° C. Vapor Pressure: 577 mmHg at 20° C.

-   Isohexane C₆H₁₄ BP=61° C. Vapor Pressure: 172 mmHg at 20° C.

-   Isoheptane C₇H₁₆ BP=90° C., Vapor Pressure: 66 mmHg at 20° C.

-   Isooctane C₈H₁₈ BP=99° C., Vapor Pressure: 41 mmHg at 21° C.

-   Tetraethvlmethane C₉H₂₀ BP=146° C., Vapor Pressure: 7.3 mmHg at 25°    C.

Isodecane C₁₀H₂₂ BP=167° C., Vapor Pressure: 2.3 mmHg at 25° C.

-   3-Methyldecane C₁₁H₂₄ BP=188° C., Vapor Pressure: N/A

-   Isododecane C₁₂H₂₆ BP=180° C., Vapor Pressure: 0.301 mmHg at 20° C.

Cycloalkanes C₆-C₈C_(n)H_(2n)

-   Cyclohexane C₆H₁₂ BP=81° C. Vapor Pressure: 78 mmHg at 20° C.

-   Cycloheptane C₇H₁₄ BP=118° C., Vapor Pressure: 22 mmHg at 20° C.

Cyclooctane C₈H₁₆ BP=149° C., Vapor Pressure: 16 mmHg at 37.7° C.

Unsaturated Acyclic HydrocarbonsC_(n)H_(2(n-m−1)),

-   n=number of carbon atoms-   m=number of double bonds    Alkenes C₆-C₁₁, C_(n)H_(2n)-   1-Hexene C₆H₁₂ BP=64° C., Vapor Pressure: 155 mmHg at 21° C.

-   1-Heptene C₇H₁₄ BP=94° C., Vapor Pressure: 101 mmHg at 37.7° C.

1-Octene C₈H₁₆ BP=122° C. Vapor Pressure: 36 mmHg at 37.7° C.

-   1-Nonene C₉H₁₈ BP=146° C., Vapor Pressure: 11 mmHg at 37.7° C.

-   1-Docene C₁₀H₂₀ BP=172° C., Vapor Pressure: 1.67 mmHg at 25° C.

-   1-undecene C₁₁H₂₂ BP=192° C. Vannr Pressure: N/A

-   1-Dodecene C₁₂H₂₄ BP=214° C., Vapor Pressure: N/A

Alkadienes: C₆-C₁₂ C_(n)H_(2n−2)

-   1,5-Hexadiene C₆H₁₀ BP=60° C., Vapor Pressure: 367 mmHg at 37.7° C.

-   2,4-Hexadiene C₆H₁₀ BP=82° C., Vapor Pressure: N/A

-   1,6-Heptadiene C₇H₁₂ BP=90° C., Vapor Pressure: N/A-   1,7-Octadiene C₈H₁₄ BP=118° C., Vapor Pressure: 19 mmHg at 25° C.

-   1,8-Nonadiene C₉H₁₆ BP=141° C., Vapor Pressure: 7 mmHg at 25° C.

-   1,9-Decadiene C₁₀H₁₈ BP=169° C., Vapor Pressure: 4 mmHg at 20° C.

-   1,10-Undecadiene C₁₁H₂₀ BP=187° C., Vapor Pressure: N/A

1,11-Dodecadiene C₁₂H₂₂ BP=207° C., Vapor Pressure: N/A

Unsaturated Cyclic HydrocarbonsC_(n)H_(2(n-m)),

-   n=number of carbon atoms-   m=number of double bonds    Cycloalkenes C₆-C₈, C_(n)H_(2n−2)-   Cyclohexene C₆H₁₀ BP=83° C. Vapor Pressure: 160 mmHg at 20° C.

-   Cycloheptene C₇H₁₂ BP=113° C., Vapor Pressure: 22 mmHg at 20° C.

-   Cyclooctene C₈H₁₄ BP=145° C. Vapor Pressure: N/A

Cycloalkadienes C₆-C₈, C_(n)H_(2n−4)

-   1,3-Cyclohexadiene C₆H₈ BP=80° C., Vapor Pressure: 56 mmHg at 25° C.

-   1,4-Cyclohexadiene C₆H₈ BP=88° C., Vapor Pressure: N/A

-   1,3-Cycloheptadiene C₇H12 BP=120° C., Vapor Pressure: N/A

-   1,3-Cyclooctadiene C₈H₁₄ BP=143° C., Vapor Pressure: 13.4 mmHg at    25° C.

Generally, the protective inert liquid layer is devoid of dissolvedand/or dispersed chemicals (e.g., salts, lubricants and/or greases) thatwould coat the surface of the battery active material layer with a solidfilm or leave behind a sticky residue. Accordingly, the protective inertliquid layer is generally devoid of dissolved salts (e.g., lithiumsalts, or more generally alkali metal salts).

In order to be inert in direct contact with the battery active materiallayer, the liquid hydrocarbon(s) should have a very low concentration ofmoisture. Preferably the concentration of moisture in the inert liquidhydrocarbon layer is less than 10 ppm of water, more preferably lessthan 5 ppm of water, even more preferably less than 1 ppm of water, andyet even more preferably less than 0.1 ppm of water (i.e., super dry).In various embodiments the inert liquid is actively dried in thepresence of sacrificial alkali metal surfaces (e.g., pieces/chips oflithium or sodium metal) that getter oxygen, water and nitrogenimpurities. Moreover, the liquid hydrocarbons may be passed through adrying a chamber in order to maintain very low moisture levels. Thedrying chamber may contain drying agents and oxygen getters. Examples ofdrying agents for liquid hydrocarbons include molecular sieves (3A, 4A,or 5A depending on the hydrocarbon type), magnesium oxide, zincchloride, calcium sulfate, calcium chloride, calcium hydride, andalumina (neutral or basic). In various embodiments, the cumulative areaof the sacrificial alkali metal surfaces in direct contact with theinert liquid is greater than the first major surface of the batteryactive material layer on which the inert liquid covers in directcontact, for instance when the battery active material layer is disposedin a protective liquid bath, as described in more detail herein below.

Depicted Embodiments

In one aspect the present disclosure provides methods for making asolid-state laminate electrode assembly. In various embodiments, thesolid-state laminate electrode assembly is a lithium metal layerreactively bonded with a lithium ion conducting sulfide glass layer.

With reference to FIG. 1 there is illustrated process flow diagram 5 formaking a solid-state laminate electrode assembly in accordance withvarious embodiments of the present disclosure.

The process includes initial operations 10 and 20, for making orproviding a first and a second standalone electrochemical materiallaminate structure, respectively. Notably, first and secondelectrochemical material laminate structures are not the same. At thispoint, before continuing to describe the process flow diagram, it isprudent to digress for a moment and address what is meant by the termstandalone electrochemical material laminate structure.

As used herein, the term electrochemical material laminate structuremeans a laminate of two or more continuous material layers, wherein atleast one of the material layers (i.e., a first material layer) is a“battery active solid material layer” having a clean (i.e.,substantially uncontaminated) and/or substantially unpassivated firstmajor surface, and another material layer (i.e., a second materiallayer) is a “protective material layer” that is inert, not batteryactive, and removably covers, in direct intimate contact, the firstmajor surface of the battery active material layer. In variousembodiments the protective material layer is a liquid phase layer of aprotective fluid, such as a super dry hydrocarbon liquid that is spreadout evenly over the first major surface of the battery active materiallayer.

Generally, the battery active material layer is highly reactive withwater and/or oxygen, and its surfaces chemically degrade or passivaterather quickly, even under dry or vacuum conditions, including that of adry air room suited for handling lithium metal (e.g., having a dew pointbetween −20 to −40° C.) or a dry Argon filled glove box (e.g., having alow moisture and oxygen content of between 1 to 5 ppm). Accordingly, theelectrochemical laminate structure is the laminate that is used toshield a battery active material layer against adverse reactions withthe environment in which it (the battery active material layer) is made,processed and/or stored. And by the term “solid battery active materiallayer” it is meant either a solid alkali metal layer (e.g., typicallyembodied herein as a lithium metal layer) or an inorganic solidelectrolyte layer (e.g., typically embodied herein as a lithium ionconducting sulfide glass). When the battery active material layer is alithium metal layer, the laminate structure is referred to generally asan alkali metal laminate structure (or more specifically in this case asa lithium metal laminate structure), and when the battery activematerial layer is an inorganic lithium ion conducting sulfide glass, thelaminate structure is referred generally as a solid electrolyte laminatestructure (or more specifically in this case as a sulfide glass laminatestructure). Furthermore, by use of the term “standalone” when referringto an electrochemical material laminate structure, such as a standalonealkali metal laminate structure or a standalone solid electrolytelaminate structure, it is meant to emphasis that the battery activematerial layer in the standalone laminate is a discrete battery activematerial layer that has not yet been combined or coupled with a secondbattery active material layer, or yet been placed in a battery cell. Forinstance, when standalone lithium laminate structures are absent of anelectrolyte and standalone sulfide glass solid electrolyte laminatestructures are absent of battery electroactive materials.

Continuing with reference to FIG. 1 the first electrochemical materiallaminate structure, which is provided or made in process operation 10 isa standalone lithium metal laminate structure, and the secondelectrochemical material laminate structure, which is provided inprocess operation 20, is a standalone sulfide glass laminate structure.Once the laminate structures are provided (or made), the protectivematerial layer on their respective first major surfaces is removedduring process operations 12 and 22, and done without physicallydamaging the surfaces. As mentioned above, in various embodiments theprotective material layer is an inert liquid phase layer of a super dryliquid hydrocarbon. Moreover, the liquid hydrocarbon employed herein asa protective material layer is selected, in part, on its ability toremain on the surface of the lithium metal or sulfide glass layer untilsuch time that it is to be controllably removed; accordingly it cannotbe allowed to evaporate off by happenstance. Processes for acceleratingand controllably removing the protective liquid layer off of the batteryactive material layer are generally performed in a chamber designed forthat purpose. Such processes include one or more of heating, vacuumsuction, blowing a jet of dry inert gas, blowing a jet of high vaporpressure protective fluid followed by vacuum suction, as well as rinsingthe surfaces progressively with protective fluids having progressivelyhigher vapor pressures.

Once the protective material layer has been removed, it is important tominimize any exposure to gaseous or vacuum environments in order tomaintain the respective battery active material layer surfaces clean andunpassivated. Accordingly, in some embodiments the chamber or conduitthrough which the battery active material layers are translated may befilled with vapor phase protective fluid right up until the layers arecombined for lamination, according to process operation 30, wherein thelayers are reactively bonded to each other.

In various embodiments, once the liquid phase layer of protective fluidhas been removed from the surface of the sulfide glass, the glass firstmajor surface may be processed and/or treated prior to laminating withlithium metal in order to engineer a solid electrolyte interphase (SEI)with improved electrochemical properties, or when the sulfide glass isnot chemically compatible with lithium metal. As described in moredetail herein below, the sulfide glass may undergo cleaning process 24A,exemplified by an ion etch treatment under an Ar plasma followed bysurface treating process 24B, wherein the cleaned glass surface may becoated with a thin lithium metal reactive precursor film or treated tomodify the surface composition of the glass (e.g., by placing the glassfirst major surface under a Nitrogen containing plasma).

The material laminate structures, methods and processes brieflydescribed above with reference to process flow diagram in FIG. 1 are nowdescribed in more detail herein below, beginning with a description ofthe various architectures embodied for the standalone material laminatestructures, followed by methods for making lithium metal layers havingsubstantially unpassivated surfaces, as well as methods for treating thesulfide glass to engineer a solid electrolyte interphase.

Standalone Electrochemical Material Laminate Structure

In one aspect the present disclosure provides a standaloneelectrochemical material laminate structure for maintaining a majorsurface of a battery active material layer in a substantiallyunpassivated and/or substantially uncontaminated condition duringstorage and/or battery cell component fabrication (e.g., fabrication ofa fully solid-state laminate electrode assembly).

In accordance with the present disclosure, the standaloneelectrochemical material laminate structure is composed of two or morecontinuous material layers, wherein at least one of the material layers(i.e., a first material layer) is a “battery active solid materiallayer” having a clean (i.e., substantially uncontaminated) and/orsubstantially unpassivated first major surface, and another materiallayer (i.e., a second material layer) is a “protective material layer”that is inert, not battery active, and removably covers, in directcontact, the first major surface of the battery active material layer.

In various embodiments the battery active material layer is highlyreactive with water and/or Oxygen, and its surfaces will chemicallydegrade or passivate rather quickly, even under fairly dry conditions ofa dry Air room (e.g., having a dew point of −20° C.) or a dry Argonfilled glove box (e.g., having a low moisture and oxygen content ofbetween 1 to 5 ppm).

In accordance with the present disclosure the protective material layer:i) minimizes, and preferably prevents, direct touching exposure betweenthe first major surface of the battery active material layer and theambient gaseous atmosphere or vacuum environment about the layer (e.g.,during handling, processing and/or storage); ii) is inert in directcontact with the first major surface; and iii) is readily removedwithout physically damaging the surface. Accordingly, in variousembodiments the protective material layer is an inert liquid (e.g., asuper dry hydrocarbon liquid) that encapsulates the surface on which itis applied, and may be evaporatively removed in the absence of solid tosolid touching contact.

In a first inventive embodiment, the battery active material layer is anelectroactive alkali metal layer having a substantially unpassivatedfirst major surface (e.g., a pristine lithium metal layer), and in suchembodiments the standalone electrochemical material laminate structureis generally referred to herein as a standalone alkali metal laminatestructure; e.g., a standalone lithium metal laminate structure.Preferably, the first major surface is pristine.

In a second inventive embodiment, the battery active material layer isan inorganic solid electrolyte layer (e.g., a lithium ion conductingsulfide glass sheet), and in such embodiments the standaloneelectrochemical material laminate structure is generally referred toherein as a standalone solid electrolyte laminate structure; e.g., astandalone sulfide glass laminate structure. In various embodiments thesulfide glass layer has a first major surface that is clean (i.e.,substantially uncontaminated).

The standalone electrochemical material laminate structure of thepresent disclosure can be constructed using a number of differentarchitectures, some of which are described in more detail herein below

With reference to FIGS. 2A-D and FIGS. 2E-H there are illustrated crosssectional depictions of standalone electrochemical material laminatestructures in accordance with various embodiments of the presentdisclosure. The main differences between the structures shown in FIGS.2A-D and those shown FIGS. 2E-H are the battery active material layer.Specifically, in FIGS. 2A-D the battery active material layer is lithiummetal, and the electrochemical material laminate structure is a lithiummetal laminate structure. In FIGS. 2E-H the battery active materiallayer is a lithium ion conducting sulfide glass, and the electrochemicalmaterial laminate structure is an inorganic solid electrolyte laminatestructure. The laminate structures may take on a variety of sharedarchitectures and these architectures are now described with referenceto a battery active material layer. Thereafter, details particular tothe lithium metal layer and to the sulfide glass layer are provided.

With reference to FIG. 2A and FIG. 2E there are illustrated fullyencapsulated electrochemical material laminate structures 100A/200E inaccordance with various embodiments of the present disclosure. Structure100A/200E is composed of: i) freestanding battery active material layer101/201 having first and second major surfaces (101 i/201 i and 101ii/201 ii) and lengthwise edge surfaces (101 iii/201 iii and 10 iv/201iv); and ii) inert liquid layer 102/202 encapsulating the major surfacesand the lengthwise edge surfaces (e.g., a super dry liquid hydrocarbonlayer). In various embodiments inert liquid layer 102/202 is a super dryhydrocarbon that fully wets out the first and second major opposingsurfaces and lengthwise edge surfaces (101 i, 101 ii, 101 iii, and 101iv as well as 201 i, 201 ii, 201 iii, and 201 iv).

With reference to FIG. 2B and FIG. 2F there is illustrated a substratesupported electrochemical material laminate structure in accordance withvarious embodiments of the present disclosure. Structure 100B/200F iscomposed of battery active material layer 101/201 and material backinglayer 103/203, which may be rigid or flexible. In various embodimentslayer 103/203 is a substrate onto which the battery active materiallayer is formed, or it (the backing layer) may be applied to secondmajor surface 101 ii/201 ii after layer 101/201 has already been formed.Inert liquid layer 102/202 encapsulates first major surface 101 i/201 i,and may additionally encapsulate its lengthwise edge surfaces, as shown.In various embodiments backing layer 103 extends beyond layer 101/201,and the inert liquid wets out the lengthwise edges, as shown. In variousembodiments, backing layer 103/203 is electronically insulating, andused generally as a supporting layer 101/201 during handling, storageand processing (e.g., as an interleave to facilitate winding andunwinding). For example, when the battery active material layer issulfide glass solid electrolyte layer 201, backing layer 103 may be aninert organic polymer (e.g., a polyethylene or polypropylene film). Inother embodiments, when the battery active material layer is lithiummetal layer 101, backing layer 103 (flexible or rigid) may beelectronically conductive, and thereon serve as a current collector in abattery cell. For instance, backing layer 103 may be a metal foil ormesh (e.g., copper), or it (backing layer 103) may be a thin copper filmdeposited on a polymer support layer (e.g., a polyester film). Whenbacking layer 103 is intended to serve as a current collector,standalone electrochemical material laminate structure 100B is sometimesreferred to herein as having electrode architecture.

With reference to FIG. 2C and FIG. 2G there is illustrated standaloneelectrochemical material layer structure 100C/200G, which, in accordancewith various embodiments of the present disclosure has, what is termedherein, a wet-decal architecture, and for this reason structure100C/200G is sometimes referred to herein more simply as a wet-decal ordecal (e.g., Li-decal 100C or sulfide glass decal 200G). Laminatestructure 100C/200G includes solid material release layer 104/204covering but not touching battery active material layer surface 101i/201 i, and inert liquid layer 102/202 sandwiched there between, andencapsulating the surface on which it is applied (101 i/201 i).

Preferably, the inert liquid of layer 102/202 completely wets outsurface 101 i/201 i as well as the surface of release layer 104/204, andthis leads to the formation of a liquid bridge between the layers and anassociated wet adhesive force that assists in maintaining the releaselayer on the battery active material during handling and processing. Thedegree of wettability may be determined by the contact angle (θ).Accordingly, in various embodiments one criterion that may be used forselecting the protective liquid is based, in part, on its ability tofully wet out the battery active material surface on which it isdisposed. To effect wetting the contact angle that the liquid makes withthe solid surface should be in the range of 0°≤θ<90°, and preferably θis near 0° for complete wet out (ε.γ., θ=0°). Preferably the ability ofthe inert liquid to wet out both surface 101 i/201 i and layer 104/204is sufficient to spread the inert liquid layer evenly and intimatelyover surface 101 i/201 i, to encapsulate it (the first major surfaces)and prevent the solid release layer from touching the battery activematerial. Preferably, inert liquid layer 102/202 is thin enough to bringabout a tight liquid bridge that is capable of maintaining the solidrelease on the battery active material during handling and processing.

Continuing with reference to FIG. 2C and FIG. 2G, in various embodimentsthe average thickness of protective liquid layer 102/202 is not greaterthan 50 μm, or not greater than 25 μm, or not greater than 10 μm, or notgreater than 5 μm, but sufficiently thick and uniform, nonetheless, toprevent contact between the release layer and surface 101 i (e.g., 50μm>t>5 μm; or 5 μm>t>100 nm). In various embodiments, inert liquid layer102/202 has an average thickness in the range of 1 μm>t>100 nm; or inthe range of 5 μm>t>1 μm; or in the range of 50 μm>t>5 μm. However, thepresent disclosure is not limited as such, and it is contemplated thatstructure 100C/200C may have pockets or isolated locations that are notcovered by protective liquid, and in such embodiments, it is especiallyimportant that release layer 104/204 is inert in contact with thebattery active material.

The wet decal architecture, as described above, has a number ofadvantages, including: i) protecting surface 101 i/102 i againstphysical damage during handling; ii) enhancing the utility and/or theability to use medium to high vapor pressure inert liquids by lesseningtheir effective evaporation rate; iii) improving protection againstdegradation of surface 101 i/201 i against impurity molecules from theambient atmosphere, as the release layer itself provides an additionalbarrier against contaminating molecules entering the protective liquidfrom the ambient atmosphere; iv) extending storage shelf life andservice lifetimes due to the additional barrier properties and lowerevaporation rate of the inert liquid layer; and finally v) the solidrelease layer may serve as an interleave for winding or stacking thelaminate structures.

With reference to FIG. 2D and FIG. 2H, in various embodiments thewet-decal architecture is sealed along its lengthwise edges by seal113/213, the seal providing an additional barrier against diffusion ofimpurity molecules from the ambient atmosphere seeping into the inertliquid layer and for minimizing evaporation of the inert liquid out fromthe laminate. When sealed, the lengthwise edges are preferably alsocovered in direct contact with inert liquid. Lengthwise edge seal113/213 may be made by heat and pressure applied between release layer104/204 and backing layer 103/203, which, in various wet-decalembodiments is simply a second release layer, similar or the same aslayer 104/204. In embodiments wherein structure 100D/200H includescurrent collector layer 103, an additional sealable backing layer may beplaced behind the current collecting layer, for sealing the lengthwiseedges. During downstream processing, when the release layer needs to beremoved, the edge seal may be broken by slicing with a sharp edge.

In various embodiments the laminate thickness, as measured from thesecond major surface of the battery active material layer 101 ii/201 iito the top surface of inert liquid layer 102/202 is no greater than 1 mmthick, and more typically no greater than 500 um thick. For instance, invarious embodiments the laminate thickness (as defined above) is lessthan 500 um, and typically less than 200 um, and in some embodimentsless than 100 um, or less than 50 um (e.g., between 5-100 um). Thelaminate thickness, as defined above, does not include the thickness ofthe solid release layer, or backing layer when present.

Nanofilm-Encapsulated Sulfide Glass Solid Electrolyte Structures

With reference to FIGS. 2I-P there are illustrated cross sectionaldepictions of nanofilm-encapsulated sulfide glass solid electrolytestructures, in accordance with various embodiments of the presentdisclosure. With reference to FIG. 2I, nanofilm-encapsulated sulfideglass solid electrolyte structure 200-21 is composed of: i) sulfideglass solid electrolyte sheet 201-Z having first and second majoropposing surfaces (201 i-Z and 201 ii-Z) and opposing lengthwise edgesurfaces 201 iii-Z/201 iv-Z; and ii) continuous inorganic nanofilm202-Z-2I which encapsulates the sulfide glass surfaces in directcontact. Not shown in FIG. 2I are the opposing widthwise edge surfacesof sulfide sheet 201-Z. In various embodiments, the opposing widthwiseedges are also encapsulated by nanofilm 202-Z-2I, and in suchembodiments solid electrolyte structure 200-2I is referred to herein asfully encapsulated (i.e., all surfaces of glass sheet 201-Z areencapsulated by nanofilm 202-Z-2I). In some embodiments, the widthwiseedges are not encapsulated, but may ultimately be shielded from theambient atmosphere by a polymeric edge sealant (also not shown).

Continuing with reference to FIG. 2I, encapsulating nanofilm 202-Z-2I isa conformal pinhole free inorganic material layer that encapsulates, indirect contact, sulfide sheet surfaces 201 i-Z, 201 ii-Z, 201 iii-Z, and201 iv-Z. The nanofilm is conformal so its surfaces adjacently alignwith the surfaces of the sulfide glass sheet on which it (the nanofilm)encapsulates. Accordingly, in a likewise fashion to that of sulfideglass sheet 201-Z, the nanofilm may be characterized similarly, ashaving first and second opposing major surfaces (202 i-Z and 202 ii-Z),opposing lengthwise edge surfaces 202 iii-Z and 202 iv-Z, and opposingwidthwise edge surfaces, not shown. Moreover, when describing certainaspects of the nanofilm, such as its composition, thickness, performanceand function, it is expedient, for descriptive purposes, todifferentiate specific portions of the continuous nanofilm, and inparticular to distinguish among those portions of the nanofilm that areadjacent the first and second sulfide glass major surfaces and thosewhich are adjacent the peripheral edge surfaces. As shown in FIG. 2I,portion 202 a-Z and portion 202 b-Z refer to those portions of nanofilm202-Z-2I which are adjacent sulfide glass major surfaces 201 i-Z and 201ii-Z,and portions of the nanofilm that encapsulate the edges of thesulfide glass sheet are referred to as edge encapsulating portions(e.g., lengthwise and widthwise nanofilm edge portions).

In various embodiments, thickness of nanofilm 202-Z-2I is a tradeoffbetween enhancing the moisture barrier properties by using a thickerfilm, and ensuring that the nanofilm is sufficiently thin to betransparent or permeable to Li-ions, so to allow lithium ions to moveacross the solid electrolyte separator without effectuating a large areaspecific resistance (ASR); e.g., the ASR of the separator is no greaterthan 200 Ω-cm², when measured in a battery cell at room temperature, andpreferably no greater than 100 Ω-cm², and even more preferably nogreater than 50 Ω-cm². Other considerations regarding nanofilm thicknessinclude time of fabrication, reliability and yield.

In various embodiments, the first and second major portions ofcontinuous nanofilm 202-Z-2I each has substantially uniform thickness,typically in the range of 1 nm to 100 nm; e.g., [(1 nm≤t<5 nm); (5nm≤t<10 nm); (10 nm≤t<30 nm); (30 nm≤t<50 nm); (50 nm≤t<100 nm)].

In various embodiments, the first and second major portions of nanofilm202-Z-2I (i.e., portion 202 a-Z and portion 202 b-Z) have uniformthickness of about 0.1 nm, 0.2 nm, 0.3 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7nm, 0.8 nm, 0.9 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 10 nm, or about 20 nm,or about 30 nm or about 40 nm or about 50 nm, or about 60 nm, or about70 nm or about 80 nm or about 90 nm or about 100 nm).

Generally, when referring to the nanofilm thickness, it is meant thethickness of the nanofilm adjacent to the first and second majorsurfaces (i.e., the thickness of the nanofilm major portions 202 a-Z and202 b-Z), as it is these surfaces which adjacently oppose the electrodesin a battery cell and therefore function electrochemically. Whereas theprimary benefit provided by the edge portion of the nanofilm is toeffect a moisture barrier and preferably enhance mechanical strength byblunting surface defects at or near the edge of the sulfide glass sheet,and so it (the edge portion of the nanofilm) should be sufficientlythick to provide a water impervious barrier (as described above). As aresult of the conformal nature of the nanofilm, the thickness of itsedge portion(s) are generally a function of the thickness of thenanofilm first and second major portions, and the edge portion thicknessis generally similar to or greater than the thickness of the majornanofilm portions, because, as described in more detail below, the edgeregions may be coated more than once when forming the continuousnanofilm. Accordingly, in various embodiments the nanofilm has an edgeportion thickness that is substantially equal to the sum of the firstand second nanofilm major portions 202 a-Z and 202 b-Z.

In various embodiments nanofilm 202-Z-2I is a continuous and conformalfilm having substantially uniform composition and first and second majorportion thicknesses less than 1000 nm, and more typically less than 500nm, and even more typically less than 200 nm. Typically, the nanofilmfirst and second major portion thicknesses are between 100 nm to 0.1 nm(e.g., between 10 nm to 1 nm).

With reference to FIGS. 2J-2P there are illustrated cross sectionaldepictions of various embodiments of nanofilm-encapsulated sulfide glasssolid electrolyte structures of the present disclosure wherein thenanofilm is configured to have a varied thickness and/or a variedcomposition relative to the position of the nanofilm along the sulfidesheet surface on which it encapsulates. In other words, nanofilm firstmajor portion 202 a-Z has a first composition and a first thickness, andnanofilm second major portion 202 b-Z has a second composition and asecond thickness.

With reference to FIGS. 2J-2K, separator structures 200-2J and 200-2Kare composed of sulfide glass solid electrolyte sheet 201-Z encapsulatedby continuous inorganic nanofilm 202-Z-2I and 202-Z-2J, respectively. Inaccordance with these embodiments, the conformal nanofilm has asubstantially uniform composition throughout and a thickness that isengineered to vary relative to the sulfide sheet surface on which itencapsulates. For solid electrolyte structure 200-2J, nanofilm thickness(T_(i)) refers to the substantially uniform nanofilm thickness adjacentsulfide sheet surface 201 i-Z (i.e., the thickness of nanofilm portion202 a-Z), and it is significantly greater than nanofilm thickness(T_(ii)), which is the substantially uniform nanofilm thickness adjacentsulfide sheet surface 201 ii-Z (i.e., the thickness of nanofilm portion202 b-Z) And for solid electrolyte structure 200-2K shown in FIG. 2K,T_(ii) (thickness of nanofilm portion 202 b-Z) is significantly greaterthan T_(i) (thickness of nanofilm portion 202 a-Z) Typically, when thethickness of the nanofilm along the major surfaces of the sulfide sheetare different, they are nonetheless generally substantially uniform. Invarious embodiments the absolute value of the difference between T_(i)and T_(ii) is between 1-5 nm, or between 5-10 nm, or between 10-20 nm,or between 20-50 nm, or between 50-100 nm.

With reference to FIG. 2L there is illustrated nanofilm-encapsulatedsulfide glass solid electrolyte structure 200-2L wherein sulfide glasssolid electrolyte sheet 201-Z is encapsulated by two continuous andconformal nanolayers (first nanolayer: 202-Z-A) and (second nanolayer:202-Z-B), which, in combination, form continuous nanofilm 202-Z-2L.Continuous nanolayer 202-Z-A encapsulates in direct contact sulfidesheet first major surface Z101 i (thus forming major nanofilm portion202 a-Z) and continuous nanolayer 202-Z-B encapsulates, in directcontact, sulfide sheet first major surface Z101 ii (thus forming majornanofilm portion 202 b-Z). In accordance with this embodiment, nanofilm202-Z-2L is configured to have an asymmetric architecture wherein thematerial composition of first nanolayer 202-Z-A is different than thematerial composition of second nanolayer 202-Z-B (i.e., the materialcomposition of the first major nanofilm portion is different than thematerial composition of the second major nanofilm portion. Withreference to solid electrolyte structure 200-2L, the asymmetric nanofilmis a contiguous planar composite of first and second nanolayers, asopposed to a stacked multi-layer, which it is not as the nanolayers donot overlap on either major surface of the sulfide glass sheet. Ratherthe contiguity of the nanolayers is realized by an overlap at the edgeportions of the glass sheet.

Additional nanofilm-encapsulated sulfide glass solid electrolytestructures having asymmetric architectures are shown in FIGS. 2M, 2N,and 2O, and described in more detail below.

With reference to FIG. 2M there is illustrated nanofilm-encapsulatedsulfide glass solid electrolyte structure 200-2M wherein sulfide glasssolid electrolyte sheet 201-Z is encapsulated by two continuous andconformal nanolayers (first nanolayer: 202-Z-A) and (second nanolayer:202-Z-B), which, in combination, form continuous nanofilm 202-Z-2M.Continuous nanolayer 202-Z-B encapsulates in direct contact sulfidesheet first major surface 201 i-Z and sulfide sheet second major surface201 ii-Z. And continuous nanolayer 202-Z-A encapsulates, in directcontact, nanolayer 202-Z-B, in that region of nanofilm 202-Z-2M which isadjacent to sulfide sheet 201 i-Z and does not encapsulate (andpreferably does not contact) nanolayer 202-Z-B in that region of thenanofilm adjacent to sulfide sheet surface 201 ii-Z. In accordance withthis embodiment, the material composition of first nanolayer 202-Z-A isdifferent than the material composition of second nanolayer 202-Z-B. Andwith reference to FIG. 2N, nanofilm-encapsulated sulfide glass solidelectrolyte structure 200-2N is similar to structure 200-2M, as shown inFIG. 2M, except that for structure 200-2N, nano layer 202-Z-Bencapsulates nanolayer 202-Z-A adjacent sulfide glass sheet surface 201ii-Z, and nanolayer 202-Z-B does not encapsulate (and preferably doesnot contact) nanolayer 202-Z-A in that region of nanofilm 202-Z-2N whichis adjacent to sulfide sheet surface 201 i-Z.

With reference to FIG. 2O there is illustrated nanofilm-encapsulatedsulfide glass solid electrolyte structure 200-20 wherein sulfide glasssolid electrolyte sheet 201-Z is encapsulated by two continuous andconformal nanolayers (first nanolayer: 202-Z-A) and (second nanolayer:202-Z-B), which, in combination, form continuous nanofilm 202-Z-2O.Continuous nanolayer 202-Z-A encapsulates in direct contact sulfidesheet first major surface 201 i-Z, and continuous nanolayer 202-Z-Bencapsulates, in direct contact, nanolayer 202-Z-A, in that region ofnanofilm 202-Z-2O which is adjacent to sulfide sheet 201 i-Z andencapsulates sulfide glass sheet surface 201 ii-Z in direct contact.Nanolayer 202-Z-A, however, does not encapsulate (and preferably doesnot contact) sulfide glass sheet surface 201 ii-Z. And with reference tonanofilm-encapsulated structure 200-2P illustrated in FIG. 2P, sulfideglass solid electrolyte sheet 201-Z is encapsulated on glass sheetsurface 201 ii-Z by nanolayer 202-Z-B and is encapsulated on glass sheetsurface 201 i-Z by nanolayer 202-Z-A, which also encapsulates nanolayer202-Z-B in that region of nano film 202-Z-P which is adjacent to sulfidesheet surface 201 ii-Z.

In various embodiments sulfide glass solid electrolyte sheet 201-Z is inthe form of a ribbon (e.g., a long narrow sheet), having substantiallyparallel lengthwise edges and a thickness in the range of 5 um to 500um, and more typically in the range of 10 um to 100 um, and even moretypically in the range of 20-50 um. In various embodiments sulfide glasssolid electrolyte sheet 201-Z is in the form a discrete sheet, typicallyat least 1 cm wide and at least 2 cm long (e.g., at least 2 cm wide andat least 5 cm long). Particularly suitable sulfide glass solidelectrolyte sheets are described in Applicant's pending patentapplications U.S. patent application Ser. No. 14/954,816 filed Nov. 30,2015 and titled Standalone Sulfide Based Lithium Ion-Conducting GlassSolid Electrolyte and Associated Structures, Cells and Methods, and U.S.patent application Ser. No. 14/954,812 filed Nov. 30, 2015 and titledVitreous Solid Electrolyte Sheets of Li Ion Conducting Sulfur-BasedGlass and Associated Structures, Cells and Methods; incorporated byreference herein for their glass composition and processing disclosures.For instance, sulfide glass compositions described therein, and whichare particularly useful as the sulfide glass composition for sheet 201-Zinclude the following specific compositional examples:0.7Li₂S-0.29P₂S₅-0.01P₂O₅; 0.71Li₂S-0.28P₂S₅-0.02P₂O₅;0.7Li₂S-0.27P₂S₅-0.03P₂O₅; 0.7Li₂S-0.26P₂S₅-0.04P₂O₅;0.7Li₂S-0.25P₂S₅-0.05P₂O₅; 0.71Li₂S-0.24P₂S₅-0.06P₂O₅;0.71Li₂S-0.23P₂S₅-0.07P₂O₅; 0.7Li₂S₅S-0.22P₂S₅-0.05P₂O₅;0.7Li₂S-0.24P₂S₅-0.06P₂O₅; 0.7Li₂S-0.23P₂S₅-0.07P₂O₅;0.7Li₂S₅S-0.29B₂S₃-0.01B₂O₃; 0.7Li₂S-0.28B₂S₃-0.02B₂O₃; 0.71Li₂S-0.27B₂S₃-0.03B₂O₃; 0.7Li₂S-0.26B₂S₃-0.04B₂O₃; 0.7Li₂S-0.25B₂S₃-0.05B₂O₃;0.71Li₂S-0.24 B₂S₃-0.06B₂O₃; 0.7Li₂S-0.23B₂S₃-0.07B₂O₃;0.7Li₂S-0.22B₂S₃-0.08B₇O₃; 0.71Li₂S-0.21 B₂S₃-0.09B₂O₃;0.71Li₂S-0.20B₂S₃-0.1B₂O₃; 0.7Li₂S-0.29B₂S₃-0.01P₂O₅; 0.7Li₂S-0.28B₂S₃-0.02P₂O₅; 0.7Li₂S-0.27B₂S₃-0.03P₂O₅; 0.7Li₂S-0.26B₂S₃-0.04P₂O₅;0.7Li₇S-0.25 B₂S₃-0.05P₂O₅; 0.7Li₂S-0.24B₂S₃-0.06P₂O₅;0.7Li₂S-0.23B₂S₃-0.07P₂O₅; 0.7Li₂S-0.22 B₂S₃-0.08P₂O₅;0.7Li₂S-0.21B₂S₃-0.09P₂O₃; 0.7Li₂S-0.20B₂S₃-0.1P₂O₅; 0.7Li₂S-0.29B₂S₃-0.01P₂O₂; 0.7Li₂0.28B₂S₃-0.02SiS₂; 0.7Li2S-0.27 B₂S₃-0.03SiS₂;0.7Li₂S-0.26 B₂S₃-0.04SiS₂; 0.7Li₂S-0.25B₂S₃-0.05SiS₂; 0.7Li2S-0.24B₂S₃-0.06SiS₂; 0.7Li₂S-0.23 B₂S₃-0.07SiS₂; 0.7Li₂S-0.22B₂S₃-0.08SiS₂;0.7Li₂S-0.21B₂S₃-0.09SiS₂; 0.7Li₂S-0.20B₂S₃-0.1SiS₂.

Particularly suitable silicon sulfide glass compositions include(1-x)(0.5Li₂S-0.5SiS₂)-xLi₄SiO₄; (1-x)(0.6Li₂S-0.4SiS₂)-xLi₄SiO₄;(1-x)(0.5Li₂S-0.5SiS₂)-xLi₃B0 ₃; (1-x)(0.6Li₂S-0.4SiS₂)-xLi₃BO₃;(1-x)(0.5Li₂S-0.5SiS₂)-xLi₃PO₄; (1-x)(0.6Li₂S-0.4SiS₂)-xLi₃PO₄; whereinx ranges from 0.01-0.2. Specific examples include:0.63Li₂S-0.36SiS₂-0.01Li₃PO₄; 0.59Li₂S-0.38SiS₂-0.03Li₃PO₄;0.57Li₂S-0.38SiS₂-0.05Li₃PO₄; and 0.54Li₂S-0.36Si S₂-0.1Li₃PO₄.

In various embodiments the composition of sulfide glass sheet 201-Z isof the type having composition: xLi₂S-yP₂S₅-zSi S₂, xLi₂S-yB₂S₃-zSiS₂,xLi₂S-yP₂S₅-zSiO₂, xLi₂S-yB₂S₃-zSiO₂, xLi₂S-yB₂S₃-zB₂O₃, orxLi₂S-yP₂S₅-zP₂O₅; wherein x+y+z=1 and x=0.4−0.8, y=0.2−0.6, and zranging from 0 to 0.2 (e.g., about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06,0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18,0.19, 0.2), and particularly x+y+z=1 and x=0.6−0.7, y=0.2−0.4, and zranging from 0 to 0.2 (e.g., z is between 0.01-0.2, such as about 0.01,0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13,0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2); and more particularly x+y+z=1and x=0.7, y=0.2−0.3, and z ranging from 0 to 0.2 (e.g., z is between0.01−0.2, such as about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08,0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2).

In various embodiments the composition of sulfide glass sheet 201-Z isof the type having composition: xLi₂S-ySiS₂-zP₂S5 or xLi₂S-ySiS₂-zP₂O₅;wherein x+y+z=1 and x=0.4−0.6, y=0.2−0.6, and z ranging from 0 to 0.2(e.g., z is between 0.01−0.2 such as about 0.01, 0.02, 0.03, 0.04, 0.05,0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17,0.18, 0.19, 0.2), and particularly wherein x+y+z=1 and x=0.5−0.6,y=0.2−0.5, and z ranging from 0 to 0.2 (e.g., z is between 0.01−0.2 suchas about 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1,0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2).

As described above, in exemplary embodiments sulfide based solidelectrolyte sheet 201-Z is a continuous vitreous sheet of sulfide glass(e.g., a monolithic sheet of sulfide glass); however, the presentdisclosure is not limited to nanofilm-encapsulated sulfide sheets ofglass, but is meant to include other moisture sensitive sulfide basedsolid electrolyte layers, such as sheets composed of Li ion conductingsulfide ceramics and glass ceramics materials that benefit from anencapsulating-nanofilm, as described herein. For instance, it iscontemplated herein that moisture sensitive sulfide solid electrolytesheet 201-Z may be formed as a continuous sheet of sulfide glass that issubsequently crystallized or partially crystallized to form a ceramic orglass-ceramic sulfide sheet, or the ceramic/glass-ceramic sulfide sheetmay be crystallized during glass sheet formation. In alternativeembodiments, sulfide based solid electrolyte layer 201-Z may be asulfide sheet formed by powder/particle compaction of Li ion conductingsulfide particles, including sulfide glass particles, sulfideglass-ceramic particles, polycrystalline sulfide ceramic particles andcombinations thereof. Such materials include thio-Lisicons and LGPS typeionic conductors. For example, Li₄GeS₄, Li₃PS₄, Li₄SiS₄,Li_(3.25)Ge_(0.25)P_(0.75)S₄, Li_(4+x)Si_(1-x)Al_(x)S₄ andLi_(4+x)Ge_(1-x)Ga_(x)S₄, Li_(4-x)Si_(1-x)P_(x)S₄ with x=0.6,Li₁₀GeP₂S₁₂, Li₇P₃S₁₁, Li₁1AlP₂S₁₂, Li₁₀SnP₂S₁₂. Sulfide based solidelectrolyte structures made by particle compaction are described in U.S.Pat. Pub. No. 20120177997; U.S. Pat. Pub. No. 20130164631; and U.S. Pat.Pub. No. 20160133989, and as described herein, may be improved upon byencapsulating one or more of the sulfide surfaces with an encapsulatingnanofilm, as described throughout this disclosure.

Nanofilm Composition and Thickness

The choice of material layer compositions for the inorganic nanofilm isinformed by the ability of that material, in dense ultra-thin form, toimpart the desired functionality and/or advantage, such as moistureimperviousness, improved mechanical strength, enhanced chemicalresistance to liquid electrolytes and oxidative stability in directcontact with cathode electroactive materials (e.g., intercalationmaterials having a voltage versus lithium metal that is greater thanabout 2.5V, or greater than about 3V or greater than about 3.5V).

In various embodiments the material composition of the nanofilm ornanolayer is an insulator in bulk form, but is transparent or permeableto lithium ions as a nano layer.

In various embodiments the nanofilm composition is a binarymetal/semi-metal oxide or metal/semi-metal nitride; the binary naturegenerally simplifies nanofilm deposition, and so is preferable, howeverthe present disclosure is not limited as such. Particularly suitablecompositions include the following and their combinations, aluminumoxide, boron oxide, zirconium oxide, yttrium oxide, hafnium oxide, andniobium oxide, tungsten oxide, titanium oxide, tantalum oxide,molybdenum oxide, zinc oxide, silicon oxide, vanadium oxide, chromiumoxide, and silicon nitride, aluminum nitride, boron nitride, tungstennitride, titanium nitride, chromium nitride, tantalum nitride, coppernitride, gallium nitride, indium nitride, tin nitride, zirconiumnitride, niobium nitride, hafnium nitride, tantalum nitride.Multi-component nanofilm compositions (e.g., tertiary, ternary, andquaternary compositions) are also contemplated herein, including oxidesand nitrides of one or more metals/semi-metals, including aluminum,boron, zirconium, yttrium, hafnium, niobium, tungsten, titanium,tantalum, vanadium, chromium, molybdenum, zinc, and silicon. Moreover,the above listed compositions may be combined with lithium to formlithium containing nanofilm compositions, including: lithiummetal/semi-metal oxides, such as lithium aluminum oxide, lithiumaluminum silicon oxide, lithium tantalum oxide and lithium niobiumoxide; and lithium metal/semi-metal nitrides, such as lithium aluminumnitride, lithium silicon nitride, lithium boron nitride and combinationsthereof. In another embodiment, the nanofilm may be a moisture resistantsulfide, such as zinc sulfide.

In particular embodiments, the nanofilm is a phosphorous oxide oroxynitride, such as a lithium phosphorous oxide (e.g., Li₃PO₄) andlithium phosphorous oxynitride (i.e., a LiPON type nanofilm) withvarious stoichiometries, including Li₂PO₂N.

In particular embodiments, the nanofilm is a phosphorous nitride (e.g.,P₃N₅), and in embodiments thereof may be a lithium phosphorous nitridedevoid of oxygen; i.e., a ternary lithium phosphorous-nitride compound(e.g., LiPN₂, Li₇PN₄).

In various embodiments, the nanofilm composition is that of an intrinsicLi ion conducting material. Intrinsic lithium ion conducting materialscomprise lithium ions, and are generally understood in the art aslithium ion conducting solid electrolyte materials. An intrinsic Li ionconducting material is, itself, Li ion conductive, and typically has aroom temperature conductivity of at least 10⁻⁷S/cm, and its ability toconduct Li ions does not depend on a second material (e.g., a materiallayer onto which it is coated). Examples of intrinsic Li ion conductingmaterial compositions which are suitable herein for use as the materialof the nanofilm or that of a nanolayer include lithium phosphorousoxynitride (e.g., LiPON), lithium titanates, lithium lanthaniumtitanates, lithium phosphate (e.g., Li₃PO₄), lithium nitrate (LiNO₃),lithium silicates, lithium tantalum oxide (e.g., LiTaO₃), lithiumaluminum oxide (e.g., LiAlO_(x)), lithium niobium oxide (e.g., LiNbO₃),lithium nitride (Li₃N), lithium silicon aluminum oxide, lithiumgermanium aluminum oxide, and lithium germanium silicon aluminum oxide.In contradistinction, nanofilm materials that are devoid of lithium, arenot intrinsic lithium ion conductors (e.g., metal oxides and metalnitrides devoid of lithium as well as phosphorous nitrides devoid ofoxygen and lithium).

With reference to FIG. 2I, in various embodiments, the nanofilmcomposition is an inert binary metal oxide (e.g., alumina, hafnia,zirconia), and the thickness of the alumina nanofilm is in the range of1 nm to 100 nm (e.g., about 1 nm, or about 2 nm or about 5 nm, or about10 nm, or about 20 nm or about 30 nm or about 40 nm or about 50 nm orabout 60 nm or about 70 nm or about 80 nm or about 90 nm or about 100nm). In particular embodiments, the inert metal oxide nanofilm fullyencapsulates all surfaces of the sulfide glass sheet and has a thicknessin the range of about 1 nm to 5 nm (e.g., about 1 nm, or about 2 nm, orabout 3 nm, or about 4 nm, or about 5 nm. It is also contemplated hereinthat some amount of moisture barrier benefit is provided from anexceptionally thin fully encapsulating nanofilm, having thickness lessthan 1 nm (e.g., about 0.1 nm, or about 0.2 nm, or about 0.3 nm, orabout 0.4 nm, or about 0.5 nm, or about 0.6 nm, or about 0.7 nm, orabout 0.8 nm, or about 0.9 nm). In another particular embodiment, theinert nanofilm may be employed to provide superior moisture barrierproperties for protecting the sulfide glass during storage. In such saidembodiments, thicker nanofilms generally provide an improved barrier;for instance, inert nanofilms with enhanced barrier properties arecontemplated herein to have thickness in the range of 5 nm to 10 nm, or10 nm to 20 nm, or 20-30 nm, or 30-40 nm, or 40-50 nm, or 50-60 nm or60-70 nm, or 70-80 nm, or 80-90 nm or 90-100 nm. In various embodiments,prior to incorporating the solid electrolyte structure into a batterycell and/or prior to depositing lithium metal onto the first majorsurface of the nanofilm, the nanofilm thickness adjacent the firstand/or second major surfaces of the sulfide glass sheet is reduced orentirely removed (e.g., by plasma etching that portion of the nanofilm).As described in more detail herein below, when making a solid-statelaminate of the present disclosure, the procedure to remove the nanofilmis performed just prior to depositing lithium metal onto the first majorsurface of the glass sheet (e.g., an inert binary metal oxide nanofilm(e.g., alumina) of thickness greater than 5 nm is entirely removed byArgon plasma etching prior to depositing lithium metal onto thatsurface).

With reference to nanofilm-encapsulated sulfide glass solid electrolytestructure 200-2L shown in FIG. 2L, nanofilm 202-Z-2L is configured tohave an asymmetric architecture wherein the thickness and/or compositionof the nanofilm first major portion is different than that of thenanofilm second major portion. In various embodiments, the asymmetricarchitecture nanofilm is composed of two nanolayers: i) first nanolayer202-Z-A, which is an inert material layer having a thickness andcomposition that provides a moisture barrier and a low resistanceinterface in direct contact with lithium metal (e.g., the ASR of thesolid electrolyte structure is less than 50 Ω-cm², and preferably lessthan 25 Ω-cm²; and ii) second nanolayer 202-Z-B having thickness andcomposition suitable for it to serve as a moisture barrier and toprovide an inert surface, which, when configured in a battery cell,opposing the cathode, is chemically compatible in direct contact withcathode electroactive material having an electrochemical potential of 3Volts or greater versus lithium metal, and therewith prevents oxidationof the sulfide glass and/or prevents dissolution of sulfide glassmaterial into the liquid electrolyte of the battery cell.

Continuing with reference to FIG. 2L, in a particular embodiment firstnanolayer 202-Z-A is an inert metal nitride and second nanolayer 202-Z-Bis an inert metal oxide (e.g., a binary metal nitride and a binary metaloxide). In a specific embodiment thereof inert metal nitride nanolayer202-Z-A is devoid of lithium metal (e.g., silicon nitride), andreactively converts to a lithiated composition when contacted withlithium metal during fabrication of a solid-state laminate electrodeassembly, as described in more detail herein below. For instance,silicon nitride (e.g., SiN, Si₃N₄, SiN_(x)) converts to Li₂SiN₂ to forma low resistance interface between the lithiated silicon nitridenanolayer and the as-deposited lithium metal layer, which is typicallyformed by evaporation. In various embodiments thickness of first majorportion 202 a-Z of silicon nitride nanolayer 202-Z-A is in the range of1 to 100 nm (e.g., in the range of 1 nm to 10 nm). Continuing withreference to nanofilm-encapsulated sulfide glass solid electrolytestructure 200-2L, in a specific embodiment second nanolayer 202-Z-B isan inert metal oxide such as aluminum oxide, zirconium oxide, andniobium oxide, with thickness in the range of 0.1 nm to 100 nm. Inparticular embodiments, the thickness of inert metal oxide nanolayer202-Z-B is in the range of 0.1 nm to 1 nm, or in the range of 1 nm to 10nm.

Continuing with reference to FIG. 2L, in another particular embodimentfirst nanolayer 202-Z-A is a phosphorous nitride devoid of oxygen (e.g.,P₃N₅) that reactively lithiates in direct contact with lithium metal(e.g., upon lithium evaporation), to form a lithiated phosphorousnitride devoid of oxygen (e.g., LiPN₂, Li₇PN₄, or a combinationthereof). In various embodiments thickness of first major portion 202a-Z of the P₃N₅ nanolayer 202-Z-A is in the range of 1 to 100 nm (e.g.,in the range of 1 nm to 10 nm).

With reference to the encapsulated sulfide glass solid electrolytestructures described and illustrated in FIGS. 2I-2P, in variousembodiments all surfaces of the sulfide glass solid electrolyte sheet201-Z are encapsulated in directed contact by the nanofilm.

In various embodiments, to achieve the requisite conformal andencapsulating features, the continuous encapsulating nanofilm and itsassociated nanolayers are deposited/coated onto the surfaces of thesulfide glass sheet via the technique known as atomic layer deposition(ALD), including PEALD (plasma enhanced atomic layer deposition). ALD isa vapor phase deposition process, and generally consists of multiplecoatings of chemical precursors that react with each other, and thesulfide sheet, to form a monolayer on the sheet surface. Forming thenanofilm using an ALD process allows for precise and accurate control ofthickness and conformality, which is an attribute that allows thecontinuous nanofilm to form and encapsulate the edge and corner surfacesof the sulfide solid electrolyte sheet. Two reviews on ALD include: i) ajournal article published in Materials Today, Volume 17, Number 5, June2014 by Richard W. Johnson, Adam Hultqvist, and Stacey F. Bent entitled“A brief review of atomic layer deposition: from fundamentals toapplications;” and ii) a journal article published in Chem. Rev. 2010,110, 111-131 by Steven M. George, and entitled “Atomic Layer Deposition:An Overview,” both of which are incorporated by reference herein fortheir disclosures relating to ALD techniques. When the sulfide sheettakes the form of a continuous web (e.g., a continuous web of Li ionconducting vitreous sulfide glass), ALD techniques for continuousroll-to-roll deposition may be used, and are described in U.S. Pat. No.9,598,769 entitled “Method and System for Continuous Atomic LayerDeposition;” U.S. Pat. No. 8,304,019 entitled “Roll-to-Roll Atomic LayerDeposition Method and System;” U.S. Pat. Pub. No.; 2007/0281089 entitled“Systems and Methods for Roll-to-Roll Atomic Layer Deposition onContinuously Fed Objects;” U.S. Pat. Pub. No. 2015/0107510 entitled“Coating a Substrate Web by Atomic Layer Deposition.” In variousembodiments, immediately prior to depositing the nanofilm (ornanolayers) the surfaces of the sulfide based solid electrolyte sheetare cleaned by plasma etching.

With reference to FIG. 2Q there is illustrated a process flow chartillustrating methods for making various embodiments ofnanofilm-encapsulated sulfide glass solid electrolyte structures inaccordance with the present disclosure. The methods include an initialoperation (operation 1) of providing (e.g., making) a sulfide glasssolid electrolyte sheet. In various embodiments, the sheet is a strip ofsulfide glass having a length to width aspect ratio of at least 2, or atleast 3 or at least 4 or at least 5 or at least 10. In particularembodiments the sulfide sheet of glass is provided as a web. In a secondoperation (operation 2), organic residue is removed from the surfaces ofthe glass sheet by any suitable technique, for example by plasmaetching, such as Argon plasma etching. Thereafter theencapsulating-nanofilm is deposited via atomic layer deposition (ALD)onto the sulfide glass sheet, and the operations for making the nanofilmvary depending on the final architecture of the nanofilm-encapsulatedsulfide solid electrolyte structure, and in particular the constructionof the nanofilm.

In various embodiments the deposition of the nanofilm takes place in twooperations. With respect to process A, as shown in FIG. 2Q, the thirdoperation (operation 3 a) involves depositing a first nanolayer via ALDonto the first major surface of the sulfide glass sheet as well as theperipheral edge surfaces of the glass. The fourth operation (operation 4a) involves depositing a second nanolayer via ALD onto the second majorsurface of the sulfide glass sheet, and the peripheral edge portions ofthe first nanolayer. Depending on the composition and thickness of thenanolayers, process A may yield a number of different nanofilmarchitectures, and three embodiments are illustrated in the process flowdiagram, Solid electrolyte structure 2P1 is formed when the secondnanolayer has the same composition and thickness as the first nanolayer(solid electrolyte structure 2Q1 is similar solid electrolyte structure200-2I shown in FIG. 2I). Solid electrolyte structure 2Q2 is formed whenthe second nanolayer has a different composition than that of the firstnanolayer, and is similar to solid electrolyte structure 200-2L, shownin FIG. 2L. Solid electrolyte structure 2Q3 is formed when the secondnanolayer has the same composition as the first nanolayer, but adifferent thickness (solid electrolyte structure 2P3 is similar to solidelectrolyte structure 200-2J or 200-2K, as shown in FIGS. 2J and 2Krespectively. With respect to process B, as shown in FIG. 2Q, the thirdand fourth operations (operation 3 b and operation 4 b) involvedepositing a first and second nanolayer via ALD onto the first andsecond major surfaces of the sulfide glass sheet, respectively. Thefirst and second nanolayers also providing encapsulation of theperipheral glass edge surfaces. The fifth operation (operation 5 b) forprocess B involves depositing a third nanolayer that encapsulates themajor surface of the first or the second nanolayer, wherein the thirdnanolayer has a different composition than that of the first and secondnanolayer. In accordance with process B, the solid electrolyte structure2Q4 thus formed is similar to solid electrolyte structures 200-2M and200-2N, as shown in FIGS. 2M and 2N, respectively. With respect toprocess C, as shown in FIG. 2Q, the third operation (operation 3 c)involves depositing a first nanolayer via ALD onto the first majorsurface of the sulfide glass sheet and the peripheral edge surfaces.This is followed by operation 4 c, which involves depositing a secondnanolayer via ALD onto the second major surface of the sulfide glasssheet, and the peripheral edge portions of the first nanolayer, andfurther wherein the second nanolayer has a different composition thanthat of the first nanolayer. This is followed by operation 5 c, whichinvolves depositing a third nanolayer via ALD onto the first nanolayer,wherein the third nanolayer has the same composition as that of thesecond nanolayer. In accordance with process C, solid electrolytestructure 2Q5 thus formed, is similar to solid structures 200-20 and200-2P, as shown in FIGS. 2O and 2P, respectively.

Liquid Phase Protective Fluid Layer

With reference to FIGS. 2A-D and 2E-H, in accordance with the presentdisclosure one function of protective material layer 102/202 (e.g.,inert liquid layer) is to removably cover and protect (e.g.,encapsulate) at least the first major surface of the battery activematerial layer, and thereon provide a degree of protection againstfacile degradation caused by direct exposure of the lithium metal layeror sulfide glass layer to ambient gaseous atmospheres during handling,processing and/or storage. By use of the term “removably cover andprotect” when describing the protective inert liquid layer it is meantthat the layer: i) covers the first surface of the battery activematerial in a manner that sufficiently protects the surface againstchemical attack; ii) remains on the first surface during handling andstorage; and iii) can be controllably removed without damaging thebattery active material layer. By use of the term “controllably remove”or “controllably removed” when referring to the protective materiallayer it is meant that the laminate structure is engineered tofacilitate removal of the protective material layer in a controlledfashion, and is otherwise not easily removed (e.g., by happenstance,such as incidental evaporation during handling and processing ofdownstream components). Accordingly, the chemical make-up and physicalproperties of the protective material layer is properly selected toenable its controlled removal without damaging the battery activematerial layer, and the laminate structure engineered to ensure that theinert material layer stays intact as a protective layer for the desiredtime frame.

In various embodiments protective material layer 102/202 is an inertliquid that intimately covers and spans substantially the first majorsurface of the battery active material layer (i.e., it is a continuousinert liquid layer). Accordingly, in various embodiments the compositionof the inert liquid is selected, in part, based on it having a lowersurface energy than the battery active material layer surface, andtherefore capable of wetting out the battery active first major surface,and, thus, intimately covering it in direct contact, the liquid flowingand spreading out evenly to span substantially the entire surface (i.e.,encapsulate the surface); e.g., encapsulate the first major surface.

Preferably inert liquid layer 102/202 readily wets the first majorsurface of the battery active material layer. In various embodiments,the wetting angle (θ) that the inert liquid makes in contact with thebattery active material layer is less than 90° (e.g., 0≤θ<90°),preferably less than 60°, more preferably less than 30°, even morepreferably θ is less than 10°, and yet even more preferably about 0°.Accordingly, in various embodiments, the ability of the inert liquidlayer to wet the battery active material layer surface is sufficient toencapsulate the one or more surfaces that it covers in direct contact.

Generally, the thickness of inert liquid layer 102/202 is less than 1mm. In embodiments the thickness of the continuous inert liquid layer isin the range of 500 to 1000 um; or in the range of 200 to 500 um; or inthe range of 100 to 200 um; or in the range of 50 to 100 um; or in therange of 20-50 um; or in the range of 10-20 um or in the range of 5-10um; or in the range of 1-5 um; or, in some embodiments, it iscontemplated that it may be less than 1 um.

In various embodiments, in order to retain inert liquid layer 102/202 onthe surface of the battery active material layer during handling andprocessing, and controllably remove it (the inert liquid layer) withoutimparting damage or leaving behind a chemical residue, the inert liquidis selected based on a combination of its vapor pressure and boilingpoint.

In various embodiments, in order to mitigate uncontrolled evaporation ofinert liquid layer 102/202, while facilitating its controlled removal,the inert liquid of the protective material layer (i.e., the inertliquid layer) is selected, in part, based on having a room temperaturevapor pressure in the range of 0.1-10 mmHg (e.g., 0.1-1 mmHg), and/orbased, in part, on having a boiling temperature in the range of 100-200°C.

In various embodiments, the inert liquid of protective material layer102/202 is selected based on having a sufficiently low vapor pressure atroom temperature (e.g., less than 10 mmHg, or less than 1 mmHg).

In various embodiments, the inert liquid of protective material layer102/202 is selected based on having a sufficiently high boiling pointtemperature (e.g., greater than 100° C., or greater than 150° C. orgreater than 200° C.).

In various embodiments the inert liquid of protective material layer102/202 is selected based on having a room temperature vapor pressurethat is less than 10 mmHg and a boiling point temperature greater than100° C.

In various embodiments protective material layer 102/202 is composed ofone or more inert hydrocarbon liquids (e.g., isododecane). Particularlysuitable hydrocarbon liquids for use as a protective material layer aresaturated hydrocarbons (e.g., having a number of carbon atoms permolecule ranging from 5 to 15).

In various embodiments the inert hydrocarbon liquid is a saturatedhydrocarbon liquid.

In some embodiments the protective inert liquid saturated hydrocarbon isa straight chain alkane (typically having between 5 and 15 carbon atomsper molecule), such as n-Pentane, n-Hexane, n-Heptane, n-Octane,n-Nonane, n-Decane, n-Undecane, n-Dodecane.

In some embodiments the protective inert liquid saturated hydrocarbon isa branched chain alkane (typically having 5 to 15 carbon atoms permolecules), such as isopentane, isohexane, isoheptane, isooctane,tetraethylmethane, isodecane, 3-methyldecane, isododecane.

In some embodiments the protective inert liquid saturated hydrocarbon isa cycloalkane, such as cyclohexane, and cycloheptane, cyclooctane.

In some embodiments the protective inert liquid hydrocarbon is anunsaturated acyclic hydrocarbon (e.g., C_(n)H_(2(n-m−1)) wherein n isthe number of carbon atoms and m is the number of double bonds), such asalkenes (e.g., 1-Hexane, 1-Octane, 1-Nonene, 1-Docene, 1-Undecene,1-Dodecene, or Alkadienes (e.g., 1,5-Hexadiene; 2,4-Hexadiene;1,6-Heptadiene; 1,7-Octadiene; 1,8-Nonadiene; 1,9-Decadiene;1,10-Undecadiene; and 1,11-Dodecadiene.

In various embodiments the inert hydrocarbon liquid is an unsaturatedhydrocarbon liquid.

In some embodiments the protective inert liquid is an unsaturated cyclichydrocarbon (e.g., of the type C_(n)H_(2(n−m)) wherein n is the numberof carbon atoms and m is the number of double bonds), such asCyclohexane, Cycloheptane, and Cyclooctene).

In some embodiments the protective inert liquid is an unsaturated cyclichydrocarbon (e.g., one or more Cycloalkadienes), such as1,3-Cyclohexadiene; 1,4-Cyclohexadiene; 1,3-Cycloheptadiene; and1,3-Cyclooctadiene).

Generally, protective inert liquid layer 102/202 is devoid of dissolvedand/or dispersed chemicals (e.g., salts, lubricants and/or greases) thatwould coat the surface of the battery active material layer with a solidfilm or leave behind a sticky residue. Accordingly, the protective inertliquid layer is generally devoid of dissolved salts (e.g., lithiumsalts, or more generally alkali metal salts).

In order to be inert in direct contact with the battery active materiallayer, the liquid hydrocarbon(s), and, more generally, the protectiveinert liquid layer should have a very low concentration of moisture.Preferably the concentration of moisture in the inert liquid hydrocarbonlayer is less than 10 ppm of water, more preferably less than 5 ppm ofwater, even more preferably less than 1 ppm of water, and yet even morepreferably less than 0.1 ppm of water (i.e., super dry). In variousembodiments the inert liquid is actively dried in the presence ofsacrificial alkali metal surfaces (e.g., pieces/chips of lithium metal)that getter oxygen, water and nitrogen impurities. In variousembodiments, the cumulative area of the sacrificial alkali metalsurfaces in direct contact with the inert liquid is greater than thefirst major surface of the battery active material layer on which theinert liquid covers in direct contact, for instance, when the batteryactive material layer is disposed in a protective liquid bath, asdescribed in more detail herein below.

Standalone Alkali Metal Laminate Structures

In accordance with the standalone electrochemical material laminatestructure embodiments described with reference to FIGS. 2A-D, thelaminate structures 100A-D are alkali metal laminate structures whereinbattery active material layer 101 is an alkali metal layer havingsubstantially unpassivated first major surface 101 i, and preferablysurface 101 i is pristine.

In various embodiments alkali metal layer 101 is a dense alkali metallayer. In various embodiments it is a lithium metal layer or sodiummetal layer. It is also contemplated that the alkali metal layer may bea lithium metal alloy or a sodium metal alloy, which may include one ormore of the following alloying elements, including Ca, Mg, Sn, Ag, Zn,Bi, Al, Cd, Ga, In and Sb. In various embodiments alkali metal layer 101is a lithium metal layer.

In various embodiments thickness of lithium metal layer 101 is typicallyno greater than 50 microns, and more typically no greater than 25microns (e.g., 50 μm≥t>30 μm; or 30 μm≥t>20 μm; or 20 μm≥t>10 μm; or 10μm≥t≥5 μm). In some embodiments lithium metal layer 101 is a thin filmcoating on a current collector having a scant amount of lithium, withthickness no greater than 5 um thick, and typically thinner, such asabout 4 μm or about 3 μm or about 2 μm or about 1 μm, or less than 1 μm(e.g., 5 μm>t≥0.1 μm). For example, the thin film of lithium metal maybe coated by evaporation onto a copper current collector in a vacuumchamber, and then prior to backfilling the chamber with a dry inert gas,such as argon or helium, the first major surface of the coated film isimmersed in protective liquid or coated with a layer of inert protectiveliquid.

In accordance with the present disclosure, in various embodiments,lithium metal surface 101 i is substantially unpassivated and preferablypristine, as defined herein below. And even more preferably, lithiummetal surface 101 i is 100% unpassivated. Preferably, lithium metalsurface 101 i is 100% unpassivated and molecularly or atomically clean.

Continuing with reference to the lithium metal laminate structuresdescribed herein above with reference to FIGS. 2A-D, in variousembodiments first major surface 101 i of lithium metal layer 101 issubstantially unpassivated (or pristine), and is able to remainsubstantially unpassivated (or pristine) for a duration of at least 10seconds, or at least 1 minute, or at least 5 minutes, or at least 10minutes when it (the laminate structure) is disposed in a dry chamberhaving a water and oxygen content of about 1 to 10 ppm (e.g., about 5ppm).

By use of the term “pristine surface” with reference to alkali metallayer 101 (e.g., a lithium metal layer), it is meant a substantiallyunpassivated lithium metal surface that is also sufficiently clean to i)facilitate complete reactive bonding to an opposing solid electrolytelayer, wherein the adherence created by the complete bond issufficiently strong to prevent mechanical non-destructive release ordelamination between the layers; and ii) effectuate a sufficientlyuncontaminated interface (with the solid electrolyte layer) that isconductive to Li ions and does not result in a prohibitively largeinterface resistance (preferably no greater than 50 Ω-cm²) between thealkali metal layer (e.g., a lithium metal layer) and the solidelectrolyte layer (e.g., a sulfide glass layer).

By “substantially unpassivated” when referring to an alkali metal layersurface (e.g., a lithium metal surface) it is meant that the surface ispredominately defined by a continuous unpassivated and substantiallyunoxidized surface region that accounts for at least 70% of the area ofthe referenced lithium metal surface (e.g., first major surface 101 i).When referring to a lithium metal layer surface as pristine it is meantthat the continuous unpassivated and substantially unoxidized surfaceregion accounts for at least 90% of the area of the referenced lithiummetal surface, and preferably at least 95%, and even more preferably thepristine surface is entirely unpassivated (i.e., 100% of the surface isunpassivated). In various embodiments, as described in more detailherein below, the substantially unpassivated or pristine surface maycontain a certain amount of discrete passivated surface portions (i.e.,passivated islands).

By “sufficiently clean” when referring to the pristine lithium metalsurface, it is meant that the continuous unpassivated and substantiallyunoxidized surface region, as described above, is not poisoned by anunduly thick non-self-limiting surface-layer, which, if otherwisepresent would preclude complete reactive bonding and strong adherence toa reactive solid electrolyte layer (e.g., as defined with respect topeel strength), and would degrade electrochemical interface properties(e.g., as defined by interface resistance, and uneven plating andstripping reactions). Notwithstanding the preference to eliminate anypoisoning of the pristine surface, a minimal non-self-limitingsurface-layer covering the continuous unpassivated region may beacceptable, as described in more detail herein below.

Top down and cross sectional depictions of alkali metal layers (e.g.,lithium metal layers) having pristine surfaces in accordance withvarious embodiments of the present disclosure are depicted in FIGS.3A-D; and for comparison, passivated lithium metal layer 3E-101 isdepicted in FIG. 3E.

Briefly, in FIG. 3A, lithium metal layer 3A-101 is shown having pristinesurface 3A-101 i that is 100% unpassivated, and molecularly oratomically clean; in FIG. 3B, pristine surface 3B-101 i of lithium metallayer 3B-101 contains a certain amount of passivating islands 3B-160dispersed on continuous unpassivated region 3B-165; in FIG. 3C, thepristine surface of lithium metal layer 3-101C is covered by minimalsurface-layer 3C-181, which defines the surface of its unpassivatedregion, and has an average thickness that is preferably less than 10 nm;and in FIG. 3D pristine surface 3D-101 i includes passivating islands23D-160 and minimal surface-layer 3D-181 which defines the surface ofits unpassivated region. Prior to describing these embodiments in moredetail, it is instructive, for the purpose of comparison, to firstdepict the make-up of a fully passivated lithium layer.

With reference to FIG. 3E, a depiction of fully passivated lithium metallayer 3E-101 which may be a lithium metal foil that was made byextrusion and/or roller reduction in a dry air, dry oxygen and/or dryCO₂ gaseous environment (e.g., dry air room), or it (layer 3E-101) maybe an evaporated thin lithium film deposited on a current collector (notshown) under vacuum in a chamber, and then breaking the vacuum bybleeding a stream of dry air, dry oxygen and/or dry CO₂ (e.g., dry air)into the chamber. The exposure to dry air immediately upon making thelithium foil/film results in the formation of passivation film 3E-179,which is a dense substantially self-limiting film of lithium oxide, andit may be several hundred angstroms thick (e.g., about 500A), orthicker, when formed in a dry room atmosphere (i.e., dry air). The exactstoichiometry of the passivating film is difficult to ascertain, and sois generally referred to as Li₂O_(x). Alternatively, if formed in thepresence of dry CO₂ gas, the composition of the passivating film isprimarily lithium carbonate. By use of the term substantially self-limiting it is meant that the passivating film, formed as such, issufficiently dense and thick to effectively block further reactions andthereby mitigate subsequent film growth. For instance, lithiumpassivating film 3E-179, once completely formed, is chemically stable toexposure to dry room air unless subjected to an atmosphere having aprohibitively high concentration of a reactive impurity such as water,which is known to breakdown lithium passivating films overtime.

With reference to FIG. 3-A, pristine surface 3A-101 i of lithium metallayer 3A-101 is 100% unpassivated and substantially unoxidized, andabsent of even a minimal surface-layer contaminant.

With reference to FIG. 3B, pristine surface 3B-101 i of alkali metallayer 3B-101 contains passivated islands 3B-160 dispersed throughoutcontinuous unpassivated and substantially unoxidized surface region3B-165. The cumulative area of the islands is less than 10% of the totalarea of the first major surface, and preferably the cumulative area isless than 5%, and even more preferably less than 1%. Preferably, thearea size of the islands does not exceed 1 mm², and more preferably doesnot exceed 0.5 mm², and even more preferably does not exceed 0.1 mm². Incertain embodiments the method of making alkali metal layer 3B-101results in first major surface 3B-101 i that is characterized aspredominately unpassivated (as opposed to pristine), wherein the area ofcontinuous unpassivated region 3B-165 accounts for less than 90%, but atleast 70%, of the area of first major surface 3B-101 i.

With reference to FIG. 3C, pristine surface 3C-101 i of alkali metallayer 3C-101 is defined, in part, by the presence of non-self-limitingminimal surface-layer 3C-181 composed of an ionically and/or covalentlybonded compound which forms as a result of alkali metal atoms of thecontinuous unpassivated region oxidizing in contact with reactiveimpurity molecules derived from the external environment about thealkali metal layer structure, and especially oxygen, nitrogen and/orwater impurities which may be present in the ambient gas or ambientvacuum of the external environment in which the alkali metal layer isformed, stored and/or handled, and/or as impurities in the protectiveliquid in which it (the pristine surface) is preserved. In variousembodiments, minimal surface-layer 3C-181 is a compound product of thealkali metal atoms reacting with one or both of oxygen and water presentas an impurity, and generally derived from the ambient gas of theexternal environment; for instance, surface-layer 3C-181, an alkalimetal oxyhydroxide compound (e.g., lithium oxyhydroxide). Minimalsurface-layer 3C-181 is not necessarily continuous as shown in FIG. 3C,and may be spread out as discrete sections over the continuousunpassivated region. When present, surface-layer 3C-181 is minimal andexceptionally thin, having an average thickness that is less than 200 Å,and more preferably less than 100 Å, and even more preferably less than50 Å or less than 40 Å or less than 30 Å. Even more preferably, thepristine surface is characterized as molecularly clean, which is to meanthat the average thickness of surface-layer 3C-181 is less than 25 Å,and even more preferably the pristine surface is atomically clean, withsurface-layer 3C-181 181 having an average thickness of less than 10 Å.

With reference to FIG. 3D, lithium metal layer 3D-101 has pristinesurface 3D-101 i which is similar to that shown in FIG. 3C in that theunpassivated surface region is defined by a minimal surface-layer3D-181, similar to 3C-181 (as described above and shown in FIG. 3C), butalso containing passivating islands 3D-160, similar to the passivatingislands described above with reference to FIG. 3B.

Methods of Making Pristine Lithium Metal Layers and Lithium Metal LayersHaving Substantially Unpassivated Surfaces

As described above, the present disclosure provides methods andapparatus' for making lithium metal layers having substantiallyunpassivated and preferably pristine surfaces, and, in particular, formaking lithium metal layers wherein at least one major surface ismaintained in its pristine or substantially unpassivated conditionunder, or immersed in, a protective fluid (e.g., a protective liquid).

With reference to FIGS. 4A-D there are illustrated apparatus' 400A-D forthe manufacture of lithium metal layer 101, having first and secondmajor opposing surfaces 101 i/101 ii, wherein at least first surface 101i is formed in direct contact with protective fluid 102 (e.g., super dryinert hydrocarbon liquid, vapor or combination thereof), and therewithsurfaces 101 i and 101 ii are substantially unpassivated, and in someembodiments pristine.

Apparatus' 400A-D may be divided into two main sections or regions.First section 410 i (typically a staging section) is where the initialstock of lithium metal 430 (e.g., an ingot or foil of lithium) ispositioned for entry or disposition into second section 410 ii (surfacegenerating section), and, in particular, surface forming chamber 450wherein lithium layer 101 and/or its pristine first surface 101 i (andoptionally 101 i) are formed in direct contact with protective fluid 402(e.g., super dry inert hydrocarbon liquid as described above). Chamber450 includes enclosure 451, and is equipped with surface forming device452, and interior environmental controls not shown. Once created,as-formed lithium layer 101 may be wound and/or stored in protectiveliquid of the same or different composition as that in which the layeritself (or at least its first surface) was generated. As shown in FIG.4A, as formed lithium layer 101 is wound to form lithium roll 401-R. Thewinding may be performed inside chamber 450 (as shown), or lithium layer101 may be fed to a separate downstream chamber for subsequent windingand storage in roll form.

In various embodiments, a lithium decal (as shown in FIG. 2D) may beformed by interleaving one or a pair of solid release layers (e.g., apolyolefin sheet or film) into the roll during winding. As describedabove, in a lithium decal of the present disclosure, the solid releaselayer is positioned on the first and/or second major surface where itkeeps the inert liquid in place, ensures that the liquid spreads evenlyover surface 101 i, mitigates evaporative losses because it (the solidrelease) enhances barrier properties, provides physical protectionagainst contact damage, enables the use of protective liquids havingrelatively high vapor pressures, and serves as an interleave whenstacking or rolling the layer(s) to avoid sticking. Once the decal iswound, surface 101 i is encapsulated by a protective liquid layer, andin some embodiments the liquid may be caused to form a sheath about thelayer, which encapsulates both first and second surfaces.

With reference to FIGS. 4A-B and FIG. 4D, in various embodiments, bothfirst and second major opposing surfaces (101 i and 101 ii; see figureinserts) are formed in direct contact with protective liquid by actionof surface forming device 452 having surface forming component(s) 456a/b that directly contact lithium metal layer 101 as it forms. As shown,surface forming device 452 may be a roller reduction mill that reducesthickness of the lithium metal layer and in so doing producessubstantially unpassivated lithium surfaces by extruding initial stock430, or lithium layer 405 (as shown in FIG. 4A), between rollers 456a/b. When roller reducing a lithium metal foil, the area of the newsurface created is proportional to the decrease in thickness.

Surface forming device 452 contacts protective liquid 402 such that aslithium metal layer 101 is formed, or surface 101 i and/or surface 101 iis created, the as-formed surfaces substantially instantaneously becomeimmersed in protective fluid (e.g., inert liquid). Once the layer isformed, the inert liquid is caused to remain on the freshly createdlithium layer surfaces (e.g., by using a solid release layer on thatsurface), typically fully encompassing (i.e., encapsulating) thesurface, and thereon protecting it (the pristine surface) from directcontact with lithium reactive constituents that may be present ascontaminants in of the ambient environment about the layer. In variousembodiments, the protective fluid in which pristine lithium metalsurface 101 a is formed may be exchanged with protective fluid having adifferent composition for downstream processing and/or storage. Forinstance, surface 101 i formed in or under a first protective liquidhaving a first vapor pressure or boiling point and that first inertliquid is replaced by a second inert liquid having a second vaporpressure or boiling point (e.g., the second liquid having a higher vaporpressure and lower boiling point than the first liquid, or vice-versa).

In various embodiments, surface forming device 452 is fully, or at leastpartially, immersed in protective fluid 402. For instance, activesurface forming component 456, may be fully submerged or encompassedinside a bath of protective liquid. To contain protective liquid 102,surface generating section 410 ii includes enclosure 451 (e.g., anenvironmental chamber). In various embodiments, the surface formingdevice, and in particular its surface forming components, are alsohoused in the enclosure.

In various embodiments protective fluid 402 is a liquid at roomtemperature (i.e., 18° C. to 25° C.) and standard pressure (1 atm), andis primarily contained in the enclosure as a liquid. In variousembodiments the interior environment of the enclosure is substantiallyfilled by inert liquid, and as described above, and in more detailherein below, in various embodiments surface forming component 456 isimmersed in the inert liquid phase protective fluid, and specificallythat portion of the surface forming component which directly contactslithium metal surface 101 i is immersed in the liquid phase.Accordingly, surface 101 i, or both surfaces 101 i and 101 bii, areformed in direct contact with liquid phase protective fluid, andpreferably the as-formed surfaces are fully encompassed/encapsulated bythe liquid phase, and as such the surfaces are formed in the absence ofdirect contact with a gaseous phase environment (e.g., dry air or aninert gas phase environment, including one or more noble gases), andthus also not formed in a vacuum environment. For instance, the lithiummetal layer and/or its associated surfaces are fully formed immersed ina protective liquid. For example, formed inside a bath of protectiveliquid or inside a chamber filled with protective vapor of an inertliquid.

As described in more detail herein below, once formed within theprotective liquid, lithium metal layer 101, or its first and/or secondmajor surface(s) 101 i/101 ii are maintained in the protective liquidfor subsequent winding to form a roll of lithium metal foil 101-R(typically on a spool) and/or storage. By this expedient, as-formedlithium metal layer 101, and/or surface 101 i, or both surfaces 101 iand 101 ii, have never been exposed to a gaseous phase environment or toa vacuum environment. In such embodiments, the lithium metal foil andits associated pristine surfaces, are formed, and thereafter stored in apristine state, never exposed in direct contact with a gaseousatmosphere. For example, the foils so formed are maintained pristineduring storage inside a bath of protective liquid for more than 24hours, or more than 1 week, or more than 1 month. The pristine foils maythen be sold and/or transported as such to a facility for manufacture ofdownstream battery cell components, including solid-state electrodelaminates and battery cells of the present disclosure. In variousembodiments the lithium foils are stored under protective liquid, andare preferably never been exposed in direct contact with gaseousatmospheres, including dry noble gases such as dry Argon gas, or dryHelium gas, or some combination thereof, or even dry air (i.e., airhaving a very low moisture content, such as that typical of a dry room).When rolled with a solid release layer, the release removably covers andprotects the substantially unpassivated lithium metal surface 101 i, andoptionally its opposing surface 101 ii. When a solid release is used theinert liquid layer is formed and sandwiched between the solid releaselayer and the lithium metal layer, and this laminate structure issometimes referred to herein as a wet-decal architecture, or more simplya wet-decal. Preferably, the inert liquid is capable of wetting out boththe lithium metal surface and the release layer.

In alternative embodiments the interior environment of chamber 450 isprimarily composed of protective fluid as a vapor. In such embodiments,the vapor molecules may condense on the as-formed lithium metalsurfaces. When a vapor phase protective fluid is used, the enclosure istypically vacuum evacuated, followed by evaporating the protectiveliquid inside the chamber to form the inert vapor. Notably, whenreferring to vapor phase protective fluid it is not meant a noble gassuch as Argon or Helium, or the like. By protective fluid in the vaporphase it is meant vapor of the inert liquid.

With reference to FIG. 4A there is illustrated apparatus 400A for makingpristine lithium metal layer 101 in protective fluid 402; for example, asuper dry liquid hydrocarbon. With particular reference to FIG. 4A,initial lithium metal stock 430 (e.g., a lithium ingot) is extruded viadie press 440 to form relatively thick freshly extruded lithium layer405 (typically in the range of 75 to 500 um thick). Specifically,lithium ingot 430 is loaded and pressed against extrusion die 444 viaplunger 442 and die plate 443, as is known in the art for makingextruded lithium foil from lithium ingots in a gaseous dry roomatmosphere.

As-formed, layer 405 is generally substantially upassivated andpreferably pristine upon exiting die 444. If formed in direct contactwith a gaseous dry room environment the freshly made lithium metalsurface would immediately start chemically reacting with the oxygen andcarbon dioxide in the dry room, which would passivate the exposedsurfaces. With respect to various embodiments of the present disclosure,because layer 405 is formed directly in protective liquid 102, its majoropposing surfaces 105 a/105 b are fully covered in direct contact withprotective liquid 102 substantially immediately upon formation (e.g., inless than one second). In the instant embodiment, thickness of layer 405is reduced in a subsequent roll reduction operation, as shown in section410 ii of FIG. 4A. Once formed, layer 405 is caused (e.g., by a pullingtension) to enter roll reduction device 452, which can be a rolling millhaving reduction work rolls 456 a/456 b, both of which are immersed inprotective liquid inside enclosure 451. Work rolls 456 a-b may be madeof compatible metal or plastic (e.g., polyacetal), or plastic coatedmetal rolls. Because the work rolls are immersed in protectivehydrocarbon liquid, the issue of lithium metal sticking to the rolls ismitigated. In various embodiments roll reduction reduces the lithiumlayer down to a thickness of no greater than 50 um. Thin lithium metallayer 101 is formed upon exiting the roller mill; the roller reductionoperation effectively transforms pristine lithium layer 405 (e.g., 500um thick) to thinner layer 101 having fresh surfaces 101 i and 101 iiformed in direct contact with protective liquid 402. Once formed, layer101 may be transferred from chamber 450 to a distinct/discrete windingchamber, or the winding device may be incorporated in chamber 450, andlayer 101 subsequently wound to yield lithium foil roll 401-R, which, inits wound condition, remains directly exposed in contact with protectiveliquid (e.g., the protective liquid forming a thin layer of liquidbetween the lithium metal layer and a solid release layer, not shown).As described in more detail herein below, and with reference to alithium roll package assembly of the present disclosure, wound roll401-R may be stored in a functional canister containing protectiveliquid of the same or different composition as that of protective liquid402, and a sealable port for ease of dispensing the lithium layer duringbattery cell or battery cell component manufacture. In variousembodiments a solid release layer is positioned on the substantiallyunpassivated lithium surface (e.g., during winding or stacking), and thelaminate structure so formed has, what is termed herein, a wet-decalarchitecture as described in more detail herein below.

In an alternative embodiment, a thin lithium foil may be formed bydirect extrusion of the lithium metal stock into a vacuum chamber, asdescribed below with reference to FIG. 4K.

Continuing with reference to FIGS. 4A-D, in various embodiments lithiummetal layer 101 is a thin lithium metal layer, typically of thickness nogreater than 50 μm, and more typically no greater than 25 μm (e.g., thethickness (t) of layer 101 is in the range of: 25 μm≥t>20 μm; or 20μm≥t>15 μm; or 15 μm≥t>10 μm; or 10 μm≥t>5 μm). The standalone lithiummetal layer may be self-supporting (if thicker than about 20 μm) orsupported on a substrate layer. As described in more detail hereinbelow, in various embodiments the lithium metal layer may be supportedon a thin substrate layer that also serves as a current collector, thecombination of current collector and thin lithium metal layer issometimes referred to herein as having an electrode architecture.

As shown in FIG. 4B, in an alternative embodiment, initial lithium stock430 may be a continuous foil of lithium (e.g., in the form of wound roll430-R). As stock 430 is already in foil form, it may be contained insidea chamber that is configured for entry into chamber 450 via portal 455,or the layer may be exposed to the ambient external environment aboutchamber 450 (e.g., a dry box or dry room environment), and in thisinstance the stock layer would have passivated surfaces. In operation,stock foil 430 is unwound and caused, by pulling tension, to extrudethrough work rolls 456 a/b immersed in protective liquid 402. Asdescribed above, once foil 430 is extruded through roller reduction mill452, it is wound in a similar fashion as described above, to formlithium roll 401-R immersed in protective liquid. In various embodimentsstock lithium foil 130 may be pre-passivated (e.g., by exposing itssurfaces to dry CO₂), and by this expedient improve reproducibility ofthe surface condition of the initial stock foil.

As shown in FIG. 4C, in yet another alternative embodiment stock foil430 may be surface treated inside chamber 450 to expose a fresh lithiumsurface in direct contact with protective fluid 402 (e.g., ground withan abrasive element such as a brush or rough polymeric sheet). Forinstance, surface forming device 456 (e.g., an abrasive brush) may bepositioned over stock foil 430 as it enters the chamber, and caused toengage with a surface of stock layer 430 to form pristine layer 101 andits associated pristine surface 101 i. In this embodiment the stock foildoes not undergo a significant reduction in thickness, as thetransformation of the foil from stock 430 to pristine layer 101 is basedon forming pristine surface 101 i in direct contact with protectivefluid 402 (e.g., liquid phase, vapor phase, or both). As shown in FIG.4C, in various embodiments the stock may be a laminate of lithium layer430 and a current collecting layer 461 in direct contact with the secondsurface of layer 430. In other embodiments, the stock is a lithium foil,and one or both surfaces are formed in the protective fluid, (e.g., bybrushing/grinding).

With reference to FIG. 4D there is illustrated yet another alternativeapparatus for making pristine lithium metal layer in the presence ofprotective fluid, and in accordance with the instant disclosure. Theapparatus is similar to that described above for fresh surfaces producedby roll reduction, except in this embodiment the work rolls 456 a/b arepositioned at the interface between the staging section 110 i andsurface forming section 110 ii. Lithium stock foil 430 is configured forentry into the chamber via roller mill 455. In particular, work rolls456 a/b effectively provide the portal into chamber 450, and theprotective liquid is distributed to completely cover the freshlyextruded surfaces (e.g., by spraying the inert liquid from nozzles 457onto one or both surfaces 101 i/ii). Chamber 450 may be held under adynamic vacuum with the protective fluid, in vapor form, or the chamberenvironment may be a combination of protective fluid in vapor form(i.e., protective vapor) and a dry noble gas such as argon or helium.

As described above, in various embodiments protective fluid 402 is aliquid. In some embodiments the interior environment of the chamber isheld under a dynamic vacuum with protective fluid in the vapor phase. Insome embodiments the protective fluid is present in the chamber in boththe vapor and liquid phases. In some embodiments the chamber issubstantially filled with liquid phase protective fluid (e.g., more than90% of chamber volume is accounted for by protective liquid). Generallythe protective fluid is a hydrocarbon composed of one or morehydrocarbon molecules that do not react in direct contact with lithiumatoms.

With reference to FIG. 4E there is illustrated another embodiment inaccordance with the instant disclosure for a process and apparatus 400Efor fabricating pristine lithium metal layer 101 using a series ofroller reduction mills (e.g., two or more). Apparatus 400E is generallydisposed in a closed environmentally controlled chamber, similar or thesame as chamber 451, as described above. Liquid phase protective fluid402 is applied directly onto the major opposing surfaces of lithiumstock 430 (e.g., by dripping or spraying), and is configured forextrusion rolling (i.e., roller reduction). Care should be taken toensure that the major surfaces are entirely covered with protectiveliquid throughout the process. Additionally, protective liquid 402 isdispensed from fluid reservoir 432 for application directly onto workroll pairs 456 a/456 b and 456 c/456 d. A further application of theprotective liquid is dispensed onto surface 101 i of the as-formedlithium metal layer 101 to ensure that the entirety of that surface iscoated with a sufficient amount of protective liquid layer 102 toencapsulate the surfaces and provide sufficient protection forconveyance of the lithium foil 101 downstream for laminating processes,or for disposition into a canister for storage as a Li roll packageassembly, as described below with reference to FIG. 6.

With reference to FIG. 4F there is illustrated top down views and crosssectional views qualitatively depicting the evolution of a lithiumsurface resulting from multiple roll reduction operations performed inprotective liquid in accordance with various embodiments of the presentdisclosure. The initial lithium foil is stock and may be pre-passivatedas shown (e.g., by treatment with carbon dioxide on its surface to forma lithium carbonate passivation layer). After the first roll reduction,the lithium thickness is reduced (as shown in the cross sectiondepiction), and the lithium carbonate passivating layer has been brokenapart to expose fresh lithium metal surfaces and scattered passivatedislands. Because the operations are performed in protective liquid, andthe lithium metal layer is maintained covered in protective liquidthroughout the entire process, the fresh formed surfaces can remainunpassivated. With each consecutive roll reduction the thickness of thelayer decreases and the area of the unpassivated surface regionincreases (also the passivated islands become smaller in size and area).As noted above, the decrease in lithium thickness is proportional to theincrease in the unpassivated surface region. Accordingly, in variousembodiments the method of making a thin lithium metal layer having apristine surface includes: i) determining a final lithium metal layerthickness; determining the thickness of the stock of pre-passivatedlithium metal layer necessary to create a pristine surface (i.e., atleast 90% of the surface is defined by the unpassivated surface region);roll reduce the stock lithium metal foil under protective liquid. Forinstance, if the desired lithium metal thickness is 25 um, starting witha 50 um passivated lithium foil will produce a surface that is just 50%passivated and 50% unpassivated, which is insufficient for forming apristine first major surface. To create a pristine lithium metal layerthat is 25 um thick from pre-passivated lithium metal foil requires thatthe stock foil be at least 250 um thick.

With reference to FIG. 4G, stock lithium foil 430 may be simultaneouslyroller extruded and laminated to substrate layer 490 (e.g., a coppercurrent collecting layer) using roller reduction mill 452 equipped withfluid dispensing reservoir 432 and work rolls 456 a/b as describedabove. Once processed, laminate structure 100B (as described withreference to FIG. 1B), has an electrode architecture that is composed oflithium metal layer 101 laminated with copper current collector 490F asthe backing layer behind second major surface 101 ii. First majorsurface of layer 101 is entirely covered, in direct contact, with liquidphase protective fluid 102 (i.e., it is encapsulated). As-formed,laminate 100B may be subsequently wound and disposed into canister 571(as shown in FIGS. 5A-B) to form laminate roll package assembly forstorage and ultimately downstream production of a lithium battery cell.In various embodiments the lithium metal layer may be roller extrudeddirectly onto an inorganic solid electrolyte layer serving as substrate,such as a lithium ion conducting sulfide glass layer ornanofilm-encapsulated sulfide glass solid electrolyte structure, theroll extrusion exposing substantially unpassivated lithium metaldirectly onto the sulfide glass to effect a reactive bond between thelayers.

In accordance with the methods and apparatus' shown in FIGS. 4A-F, theprocess operations of: i) roller reducing the thickness of stock lithiummetal foil; ii) forming freshly extruded lithium metal surfaces; iii)and laminating the second major surface 101 b to a copper currentcollector, may be performed in a conventional dry box or dry chamberhaving a noble gas atmosphere (e.g., argon or helium), with the interiorenvironment of the dry box at low moisture content, preferably less than10 ppm water, more preferably less than 5 ppm, even more preferably lessthan 1 ppm, and yet even more preferably less than 0.1 ppm. However, theembodiment is not limited to the apparatus being disposed in aconventional dry box, and in a manner similar to that shown in FIGS.4A-D, apparatus' 400E/400F may be configured inside an environmentallycontrolled chamber, similar to that of chamber 450, with an interioratmosphere primarily composed of protective fluid (e.g., protectivevapor).

With reference to FIG. 4H there is illustrated, in a cross sectionaldepiction, another embodiment in accordance with the instant disclosurefor a process and apparatus 400H for fabricating pristine lithium metallayer 101 by evaporating (e.g., thermal evaporation) the layer oncurrent collecting substrate 103. Unit 410H is the evaporator, and thevacuum chamber is not shown. In various embodiments, current collectingsubstrate 103 is a copper foil or a metallized plastic such as PETmetallized with a thin layer of copper. Substrate 103 is actively cooledduring the thermal evaporation by flowing cool Argon gas onto the secondsurface of the substrate. Optionally, the first surface of the lithiummetal layer is smoothed by ion bombardment, and the apparatus includesan ion gun (not shown), which emits low energy Argon ions onto theevaporated lithium surface (i.e., its first major surface). Whenactively cooling the substrate with Argon gas, substrate 103 is insertedinto ceramic frame 404H. Substrate 103 may be releasably sealed to theframe (e.g., via a glue or epoxy) in order to prevent the Argon gas fromreaching the opposing side of the substrate. With reference to FIG. 4I,there is illustrated in top down view cassette 400I composed ofplurality of ceramic frames 404H and substrates 103 fitted to each framefor making multiple components.

With reference to FIG. 4J, once lithium metal layer 101 has beenevaporated, its first major surface is covered by protective liquidlayer 102, which may be applied onto the lithium metal surface by agravure printing process, using gravure roll cylinder 405J havingrecessed cells that take-up protective fluid and apply it to the surfaceof the lithium metal layer is it passes through the rollers. Onceprotective liquid 102 is applied, it flows to cover the entire lithiummetal surface. The gravure cylinder is partially immersed in trough 407Jfilled with protective liquid that provides a reservoir for filling therecessed cells of roll 405J with fluid. The lithium metal layer issandwiched between the rollers and the surface tension of the protectiveliquid provides the force to extract the liquid from the cells and ontothe lithium metal surface. Thereafter, the lithium metal laminatestructure thus formed (i.e., Cu foil substrate 103/thermally evaporatedlithium metal layer 101/protective liquid layer 102) may be sandwichedbetween solid material release layers 104 for further protection.

With reference to FIG. 4K there is illustrated further apparatus andprocess for making vacuum die extruded lithium metal layers inaccordance with an embodiment of the present disclosure. Apparatus 400Kmay be divided into two main sections or regions. First section 410 i(typically a staging section) is where the initial stock of lithiummetal 430 (e.g., an ingot or foil of lithium) is positioned for entry ordisposition into second section 410 k ii (surface generating section).Lithium metal layer 401 k (e.g., foil) is fabricated by die extrusion ofstock lithium metal 430 (e.g., an ingot of lithium) directly into vacuumchamber 450 k. Specifically, lithium ingot 430 is loaded and pressedagainst extrusion die 444 via plunger 442 and die plate 443, andextrusion die 444 is configured with vacuum chamber 450 k such thatextruded foil 401 k is formed under vacuum 402 k. The vacuum dieextruded lithium metal layer 401 k, having first and second majoropposing surfaces 401 k i/401 k ii which are substantially unpassivated,and in some embodiments pristine.

Once formed, vacuum die extruded lithium layer 401 k may besubstantially immediately laminated to a second material layer, or oneor both major surfaces may be covered in protective fluid as describedabove (e.g., by using a gravure printing process). The fresh surfacesformed as a result of the extrusion are substantially unpassivated, andpreferably the vacuum chamber is sufficiently clean and at a sufficientvacuum level that the fresh surface(s) formed as a result of the vacuumextrusion (e.g., the first and/or second major surface) is pristine. Awinding device may be incorporated in chamber 450 k, and layer 401 k maysubsequently be wound to yield lithium foil roll 401 k-R, which, in itswound condition, may remain directly exposed in contact with protectiveliquid (e.g., the protective liquid forming a thin layer of liquidbetween the lithium metal layer and a solid release layer, not shown).

In various embodiments, lithium metal stock 430 is ultra-purified toallow for lithium metal layer 401 k to be formed as a thin foil havingthickness less than 50 um (e.g., about 45 um, or about 40 um, or about35 um or about 30 um or about 25 um or about 20 um or about 15 um orabout 10 um). To achieve such thin lithium metal layers in the form of acontinuous foil (e.g., of at least 50 cm length, or at least 100 cmlength) or web, lithium metal stock 430 should be purified to removeoxides and nitrides of lithium, and in particular to remove non-metallicimpurities, especially oxygen and nitrogen. Purification of lithiumingot 430 may be realized by one or more processes, including lowtemperature filtration, vacuum distillation, cold-trapping and getteringwith an active metal. To achieve die extruded lithium foil thicknessless than 50 um, inclusions (e.g., particles of nitrides and oxides)should be removed from the lithium metal stock 430. Preferably, theingot is absent of lithium nitride and/or lithium oxide inclusionshaving a size dimension greater than 1 um, and more preferably there areno such inclusions with a size dimension of 500 nm, and even morepreferably with a size dimension of 100 nm, and even more preferablythere are no such inclusions with a size dimension of 20 nm, and yeteven more preferably ingot 430 is absent of any particle inclusions.Preferably, the oxygen and/or nitrogen impurity levels present in ingot430 are less than 1000 ppm, more preferably less than 500 ppm, even morepreferably less than 250 ppm, and yet even more preferably less than 100ppm, less than 50 ppm, less than 20 ppm, and less than 10 ppm. Invarious embodiments, the method for purifying lithium metal stock 430involves removing nitrogen and/or oxygen using an active metal getter.Particularly suitable active metal getters are titanium (e.g., titaniumsponge), zirconium, beryllium and yttrium. Suitable methods for removingoxygen and nitrogen impurities from lithium metal are described in areport to the U.S. Atomic Energy Commission by E. E. Hoffman of OakRidge National Laboratory entitled “The Solubility of Nitrogen andOxygen in Lithium and Methods of Lithium Purification,” dated Mar. 17,1960, for example. In that report purification of lithium metal ismotivated by its use as a heat transfer material for cooling nuclearreactors. The use of a purified lithium metal stock, as described above,may also be used for making lithium metal foils as described herein withreference to FIG. 4A.

In various embodiments, vacuum die extruded lithium layer 401 k may belaminated to a second material layer inside the vacuum chamber whereinit (the die extruded lithium metal foil) is formed. Performing theoperations of lithium foil formation and lamination in the same vacuumchamber mitigates the need for transferring materials and the potentialthat any such transfer could lead to surface contamination. In aparticular embodiment the second material layer is a current collectorlayer (e.g., copper foil or a copper metalized polymer film). In anotherembodiment the second material layer is a lithium ion conducting solidelectrolyte, such as a sulfide glass solid electrolyte sheet or ananofilm-encapsulated sulfide glass solid electrolyte structure asdescribed herein.

With reference to FIGS. 5A-B there is illustrated a lithium metal rollassembly cartridge 500 (sometimes referred to herein as a lithium rollassembly package) in accordance with various embodiments of the presentdisclosure. Cartridge 500 includes Li decal laminate 100C in roll form100C-Roll, and entirely immersed in protective inert liquid 502, whichis itself contained in canister 571. The cartridge also includessealable port 572 and associated sealing cap 573. FIG. 5A showscartridge 500 in a hermetically closed state. FIG. 5B illustrates amechanism for removing Li-decal laminate 100C from the canister, viasealable port 572, with sealing cap 573 configured to assist indispensing the decal out of the canister. Cartridge 500 is suitable forstoring the decal over extended time periods, including hours, days, oreven weeks. The interior volume of canister 571 is substantiallyentirely filled with protective liquid, and may include moisture andoxygen gettering material, such as high surface area lithium metal inthe form of numerbable metal pieces immersed in the protective liquid.

Preferably cartridge 500 is sufficiently hermetic, and the protectiveliquid sufficiently dry (e.g., super dry), that lithium metal layer 101is able to maintain its substantially unpassivated or pristine surfacecondition for at least 60 minutes, or at least 5 hours, or at least 10hours, or at least 24 hours, or at least several days, weeks, or months(e.g., more than 3 days, more than 7 days, or more than 30 days).

Standalone Solid Electrolyte Laminate Structures

In accordance with the standalone electrochemical material laminatestructure embodiments described with reference to FIGS. 2E-H, in variousembodiments battery active material layer 201 is an inorganic alkalimetal ion conducting solid electrolyte layer, and the laminate structurein such embodiments is referred to herein as an inorganic solidelectrolyte laminate structure (e.g., a lithium ion conducting sulfideglass laminate structure). The room temperature alkali metal ionconductivity of the inorganic solid electrolyte layer is at least 10⁻⁶S/cm, preferably at least 10⁻⁵ S/cm, and even more preferably at least10⁻⁴ S/cm (e.g., between 10⁻⁵ S/cm and 10⁻⁴ S/cm or between 10⁻⁴ S/cmand 10⁻³ S/cm), with room temperature defined as 18° C.-25° C.

Continuing with reference to FIG. 2E-H in various embodiments inorganicalkali metal ion conductive solid electrolyte layer 201 is an inorganiclithium ion conductive solid electrolyte layer. In particularembodiments the inorganic lithium ion conductive solid electrolyte layeris an inorganic glass. In embodiments it is an oxide glass (in theabsence of sulfur). In various embodiments inorganic solid electrolytelayer 201 is a lithium ion conductive sulfide glass. In variousembodiments the inorganic solid electrolyte layer is moisture sensitiveand chemically reacts in contact with water, and in particular thesurface of the solid electrolyte layer degrades in the presence of theambient atmosphere of a dry room (e.g., having a dew point at or below−20° C.) or in some embodiments that of a dry Argon glove box (e.g.,having between 0.1 to 10 ppm of water). In various embodiments, solidelectrolyte layer 201 is a moisture sensitive Li ion conductive sulfideglass comprising lithium, sulfur and one or more of boron, silicon,and/or phosphorous. Particular sulfide solid electrolyte glasses thatcan benefit from incorporation into a solid electrolyte laminatestructure of the present disclosure include those described in U.S.Patent Publication No. 20160190640, which is hereby incorporated byreference for all that it contains; for example:0.7Li₂S-0.29P₂S₅-0.01P₂O₅; 0.7Li₂S-0.28P₂S₅-0.02P₂O₅;0.7Li₂S-0.27P₂S₅-0.03P₂O₅; 0.7Li₂S-0.26P₂S₅-0.04P₂O₅;0.7Li₂S-0.25P₂S₅-0.05P₂O₅; 0.7Li₂S-0.24P₂S₅-0.06P₂O₅;0.7Li₂S-0.23P₂S₅-0.07P₂O₅; 0.7Li₂S₅S-0.22P₂S₅-0.08P₂O₅;0.7Li₂S-0.21P₂S₅-0.09P₂O₅; 0.7Li₂S-0.2P₂S₅-0.1P₂O₅;0.7Li₂S-0.29B₂S₃-0.01B₂O₃; 0.7Li₂S-0.28B₂S₃-0.02B₂O₃; 0.7Li₂S-0.27B₂S₃-0.03B₂O₃; 0.7Li₂S-0.26B₂S₃-0.04B₂O₃; 0.7Li₂S-0.25B₂S₃-0.05B₂O₃;0.7Li₂S-0.24 B₂S₃-0.06B₂O₃; 0.7Li₂S-0.23B₂S₃-0.07B₂O₃;0.7Li₂S-0.22B₂S₃-0.08B₂O₃; 0.7Li₂S-0.21 B₂S₃-0.09B₂O₃;0.7Li₂S-0.20B₂S₃-0.1B₂O₃; 0.7Li₂S-0.29B₂S₃-0.01P₂O₅; 0.7Li₂S-0.28B₂S₃-0.02P₂O₅; 0.7Li₂S-0.27B₂S₃-0.03P₂O₅; 0.7Li₂S-0.26 B₂S₃-0.04P₂O₅;0.7Li₂S-0.25 B₂S₃-0.05P₂O₅; 0.7Li₂S-0.24B₂S₃-0.06P₂O₅; 0.7Li₂S-0.23B₂S₃-0.07P₂O₅; 0.7Li₂S-0.22 B₂S₃-0.08P₂O₅; 0.7Li₂S-0.21B₂S₃-0.09P₂O₅;0.7Li₂S-0.20 B₂ 5 ₃-0.1P₂O₅; 0.7Li₂S-0.29 B₂S₃-0.01SiS₂;0.7Li₂S-0.28B₂S₃-0.02SiS₂; 0.7Li2S-0.27 B₂S₃-0.03SiS₂; 0.7Li₂S-0.26B₂S₃-0.04SiS₂; 0.7Li₂S-0.25B₂S₃-0.05SiS₂; 0.7Li2S-0.24 B₂S₃-0.06SiS₂;0.7Li₂S-0.23 B₂S₃-0.07SiS₂; 0.7Li₂S-0.22B₂S₃-0.08SiS₂;0.7Li₂S-0.21B₂S₃-0.09SiS₂; 0.7Li₂S-0.20B₂S₃-0.1SiS₂.

In other embodiments inorganic solid electrolyte layer 201 mayincorporate a polycrystalline ceramic or a glass-ceramic layer (e.g., agarnet solid electrolyte layer). These include Li₆BaLa₂Ta₂O₁₂;Li₇La₃Zr₂O₁₂, Li₅La₃Nb₂O₁₂, Li₅La₃M₂O₁₂ (M═Nb, Ta) Li _(7+x)A_(x)La_(3-x)Zr₂O₁₂ where A may be Zn. These materials and methods for makingthem are described in U.S. Patent Application Pub. No. 2007/0148533(application Ser. No 10/591,714) and is hereby incorporated by referencein its entirety and suitable garnet like structures, are described inInternational Patent Application Pub. No. WO/2009/003695 which is herebyincorporated by reference for all that it contains. Suitable ceramic ionactive metal ion conductors are described, for example, in U.S. Pat. No.4,985,317 to Adachi et al., incorporated by reference herein in itsentirety and for all purposes. LiM₂(PO₄)₃ where M may be Ti, Zr, Hf, Ge)and related compositions such as Li those into which certain ionsubstitutions are made including Li_(1+x)Ti_(2−x)Al_(x)(PO₄)₃ and thelike which are known in the lithium battery arts.

Generally, the thickness of the inorganic sold electrolyte layer is in arange that is sensible for use in a battery cell, and generally depends,in part, on its ionic conductivity. In various embodiments the thicknessof the solid electrolyte layer is in the range of 200-1 um thick, andmore typically in the range of 100-5 μm, and even more typically in therange of 50-10 μm thick (e.g., about 10 μm or about 15 μm or about 20 μmor about 25 μm or about 30 μm or about 35 μm or about 40 μm or about 45μm or about 50 μm thick).

Solid Electrolyte Interphase (Engineered SEI)

With reference to FIG. 6A, there is illustrated an apparatus 600 andmethod for cleaning a sulfide solid electrolyte glass layer and treatingits surface to engineer a solid electrolyte interphase (SEI). Theapparatus includes environmental chamber 650 having a very low moistureand oxygen content (e.g., less than 1 ppm), supply roll 605-R of sulfideglass sheet in roll form, web carrier for translating sheet 201 throughcleaning chamber 620 and surface treatment chamber 630. Cleaning chamber620 is a plasma treatment chamber for ion etching the glass under Argonplasma. The ion-etching/plasma etching operation removes products ofsulfide glass hydrolysis by etching off a thin layer of glass from thesurface, typically in the range of 0.5 to 10 nm. Once surface 201 i hasbeen etched clean, it may be brought substantially immediately intocartridge 680 which is canister 681 filled with super dry hydrocarbonprotective liquid 602, as described and listed above. Cartridge 680receives the cleaned glass by rolling to form sulfide glass roll 610-R.Once immersed in the protective liquid, the cleaned surface can bepreserved as such. Cartridge 680 is suitable for storing the decal overextended time periods, including hours, days, or even weeks. Theinterior volume of canister 571 is substantially entirely filled withprotective liquid, and may include moisture and oxygen getteringmaterial, such as high surface area lithium metal in the form ofnumerous metal pieces immersed in the protective liquid.

In various embodiments the sulfide glass surface 201 i is not chemicallycompatible in contact with lithium metal, and so coatings on the glasssurface are described herein which are useful for creating a solidelectrolyte interphase (SEI), the SEI forming as a result of the coatingreacting with the substantially unpassivated lithium metal surfaceduring the operation of reactive bonding (e.g., during lamination of thelayers, typically using heat and pressure).

In various embodiments, after ion etching, sulfide glass layer 201 istranslated via the carrier web into surface treating chamber 630. Invarious embodiments surface treating chamber 630 is a second plasmaunit, and glass 201 is subjected to nitrogen plasma and/or aNitrogen/Argon plasma mixture, the process cleans the glass and alsomodifies the glass surface composition by introducing Nitrogen into/ontothe surface. Thereafter, the glass is wound into roll 610-R and immersedin protective liquid 602, as described above. In alternativeembodiments, as opposed to bringing the cleaned and Nitrogen treatedglass into protective fluid (e.g., liquid or vapor phase), it is storedin a dry oxygen free argon filled enclosure.

Continuing with reference to FIG. 6A, in another embodiment, protectiveliquid 602 contains dissolved reactive species such as Nitrogen andHalogens (e.g., iodine), which treat the glass surface as it (the glasslayer) is immersed in protective hydrocarbon liquid. Additional reactivespecies such as Nitrogen and Halogens may be injected into the canisteras well. In yet another embodiment, the glass surface may be cleaned andsurface treated in the same chamber. For example, inside chamber 620 theglass surface is cleaned with Argon plasma, and then the argon gas inthe chamber is displaced by protective fluid in the vapor phasecontaining sulfide glass reactive species such as Nitrogen or Halogens(e.g., iodine I₂ and iodine compounds).

In various embodiments the sulfide glass first major surface is treatedin chamber 630 to form a thin precursor film that reacts with lithiummetal to form an engineered solid electrolyte interphase (SEI). Variousprocesses, reagents and treatments for engineering the SEI are describedbelow.

With reference to FIG. 6B, in various embodiments a thin precursor film640 may coated onto the clean first major surface of sulfide glass 201to effect a solid electrolyte interphase via reaction with lithium metalduring lamination, and preferably via reaction with pristine lithiummetal surface.

In one embodiment precursor layer 640 is a halogen or interhalogen(diatomic or multi-atomic). For instance a monolayer, or severalmonolayers (e.g., up to 5 monolayers) of iodine or bromine molecules onthe solid electrolyte glass surface is formed by condensation from thegas or liquid phase (e.g., gaseous or liquid phase iodine).

In one embodiment precursor layer is nitrogen. For example, a monolayeror several monolayers (e.g., up to 5 monolayers) of nitrogen moleculeson the surface of the solid electrolyte gas is formed by condensation ofnitrogen onto the solid electrolyte surface (from a gas or liquidphase). In a particular embodiment the nitrogen coated onto the surfaceof the solid electrolyte glass via a liquid carrier, such as liquidhydrocarbons, containing dissolved nitrogen molecules. The liquidhydrocarbons should be dry, as defined above, especially if the solidelectrolyte is sensitive to moisture. Preferably the solubility ofnitrogen in the hydrocarbon is large. For instance, the liquid carrier(e.g., liquid hydrocarbon) having a room temperature solubility ofgreater than 1 mole (nitrogen molecule) per mole of the liquidhydrocarbon, and preferably a ratio that is greater than 1.1, and evenmore preferably greater than 1.2. Particularly suitable liquidhydrocarbons include n-Octane, n-Nonane, n-Decane, n-Undecane, andn-Dodecane.

In other embodiments the solid electrolyte surface may be coated with aprecursor of SO₂ or sulfur molecules, as described in more detail hereinbelow.

While lithium is primarily referenced as the akali metal layer materialherein, it should be understood that other alkali metals or alloys oflithium may also be used.

Examples: Coatings on Glass Electrolyte Surface to Form SEI Via Reactionwith Li

1. Halogens or Interhalogens (Diatomic or Multi-Atomic).

A monolayer, a few layers or condensed films are formed by iodine orbromine molecules on a glass surface from gas phase or from liquidphase. Halogen coating on the glass surface helps to improve wettabilityof Li metal towards glass (reactive wetting). In this case, the SEIformed on the clean Li surface consists of LiHal, in particular LiI orLiBr.

-   -   a. Halogen adsorption from the gas phase onto a glass surface at        elevated temperatures, room temperature, or low temperatures.

In order to minimize the coating thickness the source of iodine orbromine vapor is not a molecular halogen, but a halogen-containingcompound having a lower halogen vapor pressure. The coating thicknesscan be optimized by using halogen- containing compounds with appropriatevapor pressure and by adjusting duration and temperature of the coatingprocess. Among the compounds that are used as sources of halogen vaporare solid polyhalogens. Solid polyiodides with various cations describedin (Per H. Svensson, Lars Kloo, Chemical Reviews, 2003, Vol. 103, No. 5)can be used as iodine sources (these compositions are incorporated byreference herein). Applicable polyhalogens include quaternaryammonium-polyhalogen compounds, in particular, tetraalkylammoniumpolyhalogens, inorganic polyiodides, such as RbI₃ CsI₃ and Cu-(NH₃)₄]I₄,charge transfer complexes between dioxane, pyridine, polyvinyl,pyrrolidone, polyethyleneoxide and halogens (as acceptors), such aspoly(2 vinylpyridine)iodine and poly(4-vinylpyridine)bromine complexes.Other examples include metal-halogen compounds, for instance, CuI.

-   -   b. Halogen coating of a glass surface from the liquid phase

The glass surface is coated with halogens by its treatment in solutionscontaining molecular halogens (iodine, bromine) or polyhalogens that aredissolved in dry (less than 1 ppm of moisture), non-polar solvents. Inthe preferred case, the solvents are selected from a group ofunsaturated hydrocarbons or benzene and its homologues. In another case,the solvents are halogenated hydrocarbons, in particular, carbontetrachloride. In another case, the solvent is carbon disulfide. Theglass surface is brought into contact with or the glass is immersed intoa solvent containing dissolved coating material (halogens orpolyhalogens). Then the solvent is allowed to evaporate. In one case,Li—Mg or Li—Ca alloys (solid solution range) are used instead of Limetal. As a result, the SEI consists of LiI or LiBr doped withcorresponding halides of Mg or Ca and has increased Li ion conductivitydue to formation of Li cation vacancies (Schottky defects). In one case,both the glass surface and Li are treated in Halogen vapor containingatmosphere. As a result, the halogen coating (preferentially, a verythin coating that consists of one or two molecular layers) is formed onthe glass surface and a thin layer of LiHal is formed on the Li surface.After Li lamination onto glass, halogen molecules react with LiHal layeron Li forming an SEI consisting of a LiHal layer with increasedthickness.

2. Nitrogen

A monolayer, a few layers or condensed films formed by nitrogenmolecules on a glass surface from gas phase or from liquid phase at RTor low temperatures. At RT only one or two layers of nitrogen moleculesare adsorbed onto metal surfaces. Nitrogen can be adsorbed onto glasssurfaces either in pure Nitrogen atmosphere (the volume having beenpreviously evacuated to high vacuum) or in a mixed nitrogen/inert gasatmosphere (Ar/N₂). In order to coat a long strip of glass, either aflow of pure nitrogen or a flow of carrier gas (Ar) mixed with nitrogencan be used.

In various embodiments, the resulting SEI is, or includes, Li₃N with ahigh Li ion conductivity.

In various embodiments the molecular nitrogen precursor layer is formedby coating the surface of the solid electrolyte glass sheet with a thinlayer of a liquid hydrocarbon containing an amount of dissolved nitrogenmolecules. In various embodiments the mole ratio of nitrogen moleculesdissolved in the hydrocarbon carrier liquid is at least 0.05 moles ofNitrogen molecules per mole of liquid hydrocarbon(N₂-moles/liq.hyd-moles), for instance, at least 0.1N₂-moles/liq.hyd-moles, at least 0.2 N₂-moles/liq.hyd-moles, at least0.3 N₂-moles/liq.hyd-moles, at least 0.4 N₂-moles/liq.hyd-moles, atleast 0.5 N₂-moles/liq.hyd-moles, at least 1.0 N₂-moles/liq.hyd-moles.Particular suitable liquid hydrocarbon carriers are n-Octane, n-Nonane,n-Decane, n-Undecane, and n-Dodecane.

When using a liquid carrier containing dissolved nitrogen molecules, theSEI formed when the nitrogen coated solid electrolyte layer is directlycontacted with lithium metal is a lithium nitride compound (e.g., Li₃N),preferably fully reduced and highly conductive to lithium ions. Asdescribed above, the formation of the SEI may be effected during thelamination operation, and the liquid hydrocarbons on the surface of thesolid electrolyte layer and/or the lithium metal layer removed prior toand/or as a result of bond laminating the layers together.

3. SO₂

-   -   a. SO2 adsorption from the gas phase onto a glass surface at        elevated temperatures, RT or low temperatures. SO2 can be        adsorbed onto glass surfaces either in pure SO2 atmosphere (the        volume having been previously evacuated to high vacuum) or in a        mixed SO2/inert gas atmosphere (Ar/SO2).    -   b. SO2 coating of a glass surface at low temperature using        liquid SO2. In various embodiments, the resulting SEI is, or        includes, Li2S2O4, which is a known Li ion conductor.

4. Sulfur

-   -   a. Sublimation onto glass surface. S8 ring sulfur is known to be        the dominant sublimation phase.    -   b. Glass surface oxidation leading to formation of an elemental        S layer. In various embodiments, the resulting SEI is, or        includes, Li2S.        Solid-State Laminate Electrode Assembly

With reference to FIG. 7 there is illustrated standalone fullysolid-state laminate electrode assembly 700 in accordance with variousembodiments of the present disclosure. Laminate electrode assembly 700is a laminate of alkali metal layer 101 having first major surface 101 iand ii) inorganic alkali metal ion conducting solid electrolyte layer201 having first major surface 201 i. In various embodiments the alkalimetal layer is a lithium metal layer and the inorganic solid electrolytelayer is an inorganic lithium ion conducting sulfide glass sheet, alsoas described above. In various embodiments, laminate 700 is formed byreactively bonding layer 101 (lithium metal) with layer 201 (sulfideglass) to form inorganic interface 705 (also referred to herein as thesolid electrolyte interphase (SEI)) as 4/5 described in more detailherein below. The thickness of laminate 700 generally ranges from about100 um down to as thin as about 5 um, and typically has a thickness inthe range of 10 to 50 um. Preferably, the lithium ion resistance acrossthe interface is less than 50 Ω-cm², and more preferably less than 25Ω-cm².

The quality of inorganic interface 705 can be an important aspect fordetermining how well the laminate electrode assembly will operate in abattery cell. Preferably, inorganic interface 705 is substantiallyuncontaminated by organic material, including organic residues of anyinert liquid that may have been used in making, storing and processingof the laminate structures. In various embodiments the inorganicinterface may be further characterized as “sufficiently uncontaminatedby passivated alkali metal,” by which it is meant that at least 70% ofthe geometric area of the solid-state interface is uncontaminated by thepresence of passivated alkali metal, such as patches of passivatedalkali metal film (i.e., filmy patches), as well as pieces of passivatedalkali metal that break off during battery cell cycling and/or handling,and could become trapped at the interface in the form of solid flakes,flecks or material bits of passivated alkali metal. Preferably, at least80% of the geometric area of the solid-state interface is uncontaminatedas such, and more preferably at least 90%, and even more preferably atleast 95%, and yet even more preferably the entire geometric area of thesolid-state interface is uncontaminated by the presence of passivatedalkali metal flakes, flecks, filmy patches or material bits. To achievean inorganic interface that is sufficiently uncontaminated by passivatedalkali metal, surface 101 i of lithium metal layer 101 should besubstantially unpassivated prior to bonding, and preferably the lithiummetal layer surface is pristine. Additionally, the surface of thesulfide glass should be cleaned (e.g., by ion etching) immediately priorto bonding in order to remove solid products of sulfide glasshydrolysis.

When the reactive bond between the layers is continuous and complete,the laminate should exhibit exceptional adherence. In variousembodiments the reactively bonded solid-state interface impartsexceptionally high peel strength to the standalone solid-state laminateelectrode assembly (i.e., room temperature peel strength). For instance,the room temperature peel strength of the solid-state laminate electrodeassembly is significantly greater than the tensile strength of thelithium metal layer to which it is bonded, such that during roomtemperature peel strength testing the lithium metal layer starts todeform, or tears, prior to peeling.

Methods of Making a Solid-State Laminate Electrode Assembly

With reference to FIG. 8A there is illustrated a process and apparatus800 for making a fully solid-state laminate electrode assembly 700 inaccordance with various embodiments of the present disclosure. Theprocess takes place in an environmentally controlled chamber 850, andinvolves: i) providing a lithium metal laminate structure for processinginto chamber 850, the laminate structure (as described above withreference to FIGS. 1A-D), the laminate structure composed of lithiummetal layer 101 removably covered by protective inert liquid layer 102,which encapsulates first major surface 101 i, and second major surface101 ii is held adjacent to current collector layer 103; providing forprocessing into chamber 850 an inorganic solid electrolyte laminatestructure (as described above in various embodiments with reference toFIGS. 2A-D, the laminate composed of sulfide glass layer 201 havingfirst major surface 201 i encapsulated by protective liquid layer 202.As shown in FIG. 8A, sulfide glass layer is supported on its secondmajor surface 102 ii by web carrier 805, which is not a component of thesulfide glass laminate structure. When the laminate structures include asolid release layer, it is removed on a take-up roll not shown. Bothlayers 101 and 201 enter chamber 830 for removing the inert liquid layer102 and 202 respectively. Removal of the inert liquid layer can involvea series of operations which may be performed sequentially and/or inparallel. In various embodiments one or more of the following operationsis taken to remove the inert liquid layer, including: applying heat tothe layers (convectively and/or conductively), applying a vacuum suctionover the respective layers, applying a jet of dry gas (Ar or Hepreferably) and/or a jet of a high vapor pressure hydrocarbon, replacinga low vapor pressure fluid with another higher pressure fluid, or somecombination thereof.

Once the liquid layer has been removed from sulfide glass surface 201 i,the surface may be cleaned in ion etching chamber 820, for example,using Argon plasma (as described above with reference to chamber 620 inFIG. 6). The cleaned sulfide glass may then be transferred into surfacetreating station 850 where it may undergo a second plasma treatment withNitrogen or a mixture of Nitrogen and Argon, or it may be coated inchamber 850 to form a thin precursor film that is reactive withsubstantially unpassivated lithium metal to form a conductive solidelectrolyte interphase. For instance, in various embodiments it may becoated with a thin layer of iodine or an iodine compound (e.g.,condensing the iodine on the glass surface). Once the glass has beencleaned and/or its surface composition modified or coated with a thinprecursor film, layers 101 and 201 are brought into laminating station860 where they are reactive bonded to each other, generally by anapplication of both heat and pressure (via rollers 812) to form a fullysolid-state laminate electrode assembly of the present disclosure.

A solid-state laminate electrode assembly includes a lithium ionconducting sulfide glass solid electrolyte sheet coated on its firstmajor surface with a lithium metal layer by thermal evaporation withoutdevitrifying the sulfide glass solid electrolyte sheet. The glass sheetis preferably freestandable and typically of thickness in the range of10 um to 100 um, and more typically in the range of 20 to 50 um thick.The sheet may be positioned in a cooling fixture, such as a ceramicframe, and sealed to the frame via a releasable glue or epoxy, and thesheet is actively cooled during the thermal evaporation, for example byflowing a cryogenic fluid such as cool Argon gas onto the second majorsurface of the sheet (e.g., the cool Argon gas derived from a cryogenictank of liquid Argon). The cooling of glass substrate sheet issufficient to prevent the glass from fully or partially devitrifying andto prevent the heat of the evaporative process from damaging the surfaceof the glass. For instance, in various embodiments the temperature ofthe sulfide glass sheet is kept to 100° C. or less during theevaporation process, by application of the cooling gas. By activelycooled it is meant that the sulfide glass sheet is cooled while theevaporation of lithium metal is taking place. For instance, the coolingfluid (e.g., cool Argon gas) contacts the sulfide glass second majorsurface and it (the gas) is applied to the surface at a temperature thatis no greater than 10° C., or no greater than 0° C., or no greater than−10° C., or no greater than −20° C. When actively cooling the sulfideglass sheet during evaporation, the sheet is preferably releasablysealed to the ceramic frame in order to prevent the cool Argon gas fromreleasing into the vacuum chamber of the lithium metal evaporator orfrom diffusing into the evaporating lithium flux (e.g., the edges of theglass sheet glued to the frame, such as with an epoxy). In otherembodiments the sulfide glass sheet may be passively cooled, which is tomean cooled to a temperature below 15° C. prior to evaporating thelithium metal onto the glass first major surface. Typically whenpassively cooled the sulfide glass sheet is at a temperature that isless than 10° C. prior to evaporation, or less than 0° C., or less than−10° C., or less than −20° C. In some embodiments the substrate is bothactively cooled and passively cooled as described above. In otherembodiments the substrate is exclusively passively cooled (i.e.,passively cooled and not actively cooled), or vice versa exclusivelyactively cooled.

With reference to FIG. 8B there is illustrated another process andapparatus 800B for making fully solid-state laminate electrode assembly801B wherein thin lithium metal layer 803B is thermally evaporated,under vacuum, onto first major surface z801 i of lithium ion conductingsulfide glass substrate Z801. In various embodiments glass substrateZ801 may be solid electrolyte sheet 201 as described above withreference to FIGS. 2E-H or nanofilm encapsulated sulfide glass solidelectrolyte structures 200-2I-200-2P, as described with reference toFIGS. 2I-P.

Continuing with reference to FIG. 8B, apparatus 800B includes thermalevaporating device 410H, which includes a crucible for containing thesource of molten lithium and a vacuum chamber, both of which are notshown. Glass substrate Z801 is preferably freestandable andsubstrateless, and typically of thickness in the range of 5 um to 100um, and more typically in the range of 10 to 50 um thick.

In various embodiments lithium metal layer 803B is an ultra-thin layerthat is less than 1 um (e.g., about 0.9 um, about 0.8 um, about 0.7 um,about 0.6 um, about 0.5 um, about 0.4 um, about 0.2 um, or about 0.1um). When ultra-thin, the lithium metal layer may be deposited directlyonto first major surface Z801 i without actively removing heat away fromsubstrate Z801.

In accordance with the present disclosure, in various embodiments athermal path for removing heat away from substrate Z801 is provided viaa heat transfer fluid, which allows deposition of thicker lithium metallayers without damaging the glass surface or causing it to devitrify(e.g., 2-10 um thick), and has benefit for ultra-thin layers as well,including that it allows for higher deposition rates and improvedinterface properties. Continuing with reference to FIG. 8B, apparatus800B includes cooling fixture 833 for holding and cooling substrate Z801during thermal evaporation. Cooling fixture 833 may be a singlesubstrate fixture, or a multiple substrate fixture as shown in crosssectional view in FIG. 8B and in top down view shown in FIG. 8C. Fixture833 includes material frame 835 with recessed portion 841 for receivingsubstrate 833 and backplane 837. The recessed portions of the framedefine discrete receptacles into which glass substrate Z801 is mounted,and may be peripherally adhered to the frame via grease or an adhesive.Frame 835 is shaped to include recessed compartment 842 that serves as avolume gap between the glass substrate and backplane 837, and into whichheat transfer fluid 821 (e.g., a cryogenic fluid such as Argon gas) isdisposed or caused to flow through during the lithium metal evaporationoperation. Volume gap 842 is coupled to heat transfer fluid source 861(e.g., a tank of cryogenic Argon) via piping system 839 for admittingthe Argon gas into fixture 833, and may be interconnected to the otherreceptacles via the piping network (as shown). Generally, piping system839 includes regulation controls and valves for adjusting/controllingthe pressure, temperature and flow rate of Argon gas injected intovolume gap 842 via piping system 839. Preferably, volume gap 842 has avery small gap-dimension between the backplane and the second majorsurface Z801 ii of substrate Z801. In various embodiments thegap-dimension is between 10 to 25 um, and in some embodiments the gapmay be less than 10 um. Preferably, the second surface of the substratedoes not touch backplane. Generally, the gap is less than 50 um,although it is not intended to be limited as such, thicker gaps arecontemplated provided they are capable of removing a sufficient amountof heat to prevent glass damage during the evaporation operation.

In various embodiments heat transfer fluid 821 (e.g., cold Argon gas),which is admitted into volume gap 842 via piping system 839, is forcedto flow through gap 842 during the evaporation process, and therewithprovides a convective cooling effect. In other embodiments, cold Argongas injected into the gap prior to the lithium evaporation operationprovides sufficient cooling to prevent glass damage as a result of thethermal evaporation. When referring to the Argon gas as cold it is meantthat it is at a temperature that is less than 20° C., and typically lessthan 10° C. In various embodiments, the gas supply is cryogenic Argongas.

In various embodiments, the pressure, flow rate and temperature of Argongas 821 is adjusted and controlled to maintain the temperature of thesulfide glass substrate within a particular temperature range, or belowa particular temperature value, such as the glass transition temperatureof the sulfide glass solid electrolyte sheet (T_(g)). In particularembodiments, the thermal path provided by the Argon gas is sufficient tomaintain the temperature of the sulfide glass substrate below atemperature value that is at least 10° C. lower than the T_(g) value, orat least 20° C. lower than the value, or at least 50° C. lower than theT_(g) value, or at least 100° C. lower than the T_(g) value.

In various embodiments the temperature of glass substrate Z801 iscontrolled during the evaporation by adjusting/controlling the Argon gastemperature, pressure and flow rate through fixture 833. In particularembodiments the temperature of sulfide glass substrate Z801 during thelithium evaporation operation is maintained in a range that is less thanthe glass transition temperature of the sulfide glass solid electrolytesheet and no less than 40° C., or 60° C. or 80° C. For example, the heattransfer is controlled to maintain the glass substrate temperaturewithin a range between 40° C. to 100 and preferably between 60° C. to80° C. during the evaporation operation.

In various embodiments, prior to evaporating the lithium metal layeronto the sulfide glass substrate, first surface z801 i is ion etched(e.g., as described herein with an Ar or other suitable plasma).Preferably the ion-etching operation takes place in the same vacuumchamber as the thermal evaporation, or the ion-etching and thermalevaporation tools/units are combined/arranged as a cluster tool, whichallows for automatic transfer of the substrate between process chambers.Once the lithium metal layer is deposited onto the surface of the glass,a copper current collector may be applied onto the exposed lithium metalsurface (e.g., evaporated or sputter deposited).

With reference to FIG. 8D there is illustrated solid-state laminateelectrode assembly Z800D composed of nanofilm-encapsulated sulfide glasssolid electrolyte structure Z801, as described herein in accordance withvarious embodiments of the present disclosure, and lithium metal layerZ811 in direct contact with the first major surface of the encapsulatingnanofilm. For example, lithium metal layer Z811 evaporated onto thefirst major surface of the nanofilm.

In various embodiments nanofilm encapsulated sulfide glass solidelectrolyte structure Z801 has an asymmetric architecture such as thoseembodied in FIGS. 2L, 2M, 2N and 2O. In particular embodiments the firstmajor surface of the nanofilm is defined by a material composition thatis devoid of lithium, and reactively transforms in contact withevaporated lithium metal to form a lithiated composition, which, inturn, leads to a low resistance interface between the evaporated lithiummetal layer Z811 and the nanofilm. In a specific embodiment the firstnanolayer is silicon nitride (e.g., SiN) and it reactively lithiates toform a lithiated compound (e.g., Li₂SiN₂). In another specificembodiment the first nanolayer is a phosphorous nitride devoid oflithium and oxygen (e.g., P₃N₅) and it reactively lithiates in contactwith evaporated lithium to form a lithiated compound (e.g., LiPN₂,Li₇PN₄, or a combination thereof). Moreover, for the above embodiments,the second nanolayer is generally unchanged as a result of thelithiation reaction (e.g., the second nanolayer may be an inert oxidesuch as alumina or zirconia), and after lithium metal is evaporated ontothe first major surface of the nanofilm, the composition of the secondnanolayer does not change (i.e., the evaporation of lithium metal doesnot lithiate the second nanolayer).

In various embodiments the nanofilm has a silicon nitride or aphosphorous nitride nanolayer, and when lithium metal is thermallyevaporated onto it, the nanolayer is reactively lithiated. For instance,when the nanolayer is silicon nitride (e.g., SiN) or a phosphorousnitride devoid of oxygen the reaction product formed as a result oflithium metal evaporation is lithiated silicon nitride (e.g., Li₂SiN₂)and lithiated phosphorous nitride (e.g., LiPN₂, Li₇PN₄, or a combinationthereof), respectively.

In various embodiments lithium metal layer Z811 is deposited by thermalevaporation (as described throughout this specification), and layer Z811typically not greater than 10 um and more typically not greater than 5um thick. In various embodiments, ALD of the nanofilm is immediatelyfollowed by lithium evaporation using a combination or cluster tool thatincludes both an ALD tool and a lithium metal evaporation tool, andoptionally an ion etch tool for cleaning the sulfide sheet prior todepositing the nanofilm. The combination of these processes and tools ina cluster provides significant fabrication advantages. Such acombination/cluster tool is illustrated in FIG. 8E. In particularembodiments tool 800E is engineered to interface with glove/dry box 896E(e.g., the sulfide solid electrolyte sheet may be fabricated and/orstored in box 896E). In addition to lithium thermal evaporationunit/tool 891E, the combination tool also includes ALD tool 892E, andplasma ion-etch tool 893E. As illustrated, the cluster tool is arrangedto interface with glove box 896E for receiving the sulfide glass sheet.In various embodiments cluster tool 800E may further include a sputterdeposition tool, for depositing lithium metal directly onto the sulfidesheet or the nanofilm, and/or for sputter depositing a metal currentcollector onto the exposed surface of the as-evaporated lithium metallayer. In other embodiments lithium metal layer Z811 may be a lithiumfoil laminated onto the nanofilm.

Once the nanofilm is formed, lithium metal may be evaporated directlyonto the nanofilm first major surface using a single tool for both ALDdeposition and lithium metal evaporation, and thus mitigating exposureto ambient air. Or the solid electrolyte structure may be removed fromthe ALD chamber for storage and then transferred to a lithiumevaporation station. In various embodiments, prior to lithiumevaporation, the first major surface of the nanofilm is cleaned by Argonor other suitable plasma etching. In some embodiments, the Argon etchingoperation may be utilized to remove a substantial thickness portion ofthe nanofilm, and in certain embodiments thereof it removes the nanofilmentirely in that portion which is adjacent the first major surface ofthe sulfide glass (i.e., the Argon etching operation removes thenanofilm first major portion, thus exposing the sulfide glass forevaporation of lithium metal directly onto the sulfide glass first majorsurface.

With reference to FIG. 8F there is illustrated a process flow diagramillustrating methods for making solid-state laminate electrodeassemblies made by evaporating lithium metal onto ananofilm-encapsulated sulfide glass solid electrolyte structure. Theinitial operation is providing a nanofilm-encapsulated sulfide glasssolid electrolyte structure in accordance with various embodiments ofthe present disclosure. In a first process (Process D), the majoropposing surfaces of the nanofilm are cleaned by etching the nanofilmsurfaces in an Argon or other suitable plasma, and immediatelythereafter lithium metal is evaporated onto the first major surface ofthe nanofilm, and typically the lithium thickness is in the range of lumto 10 um (e.g., about lum or about 2 um, or about 5 um or about 10 um).In a second process (Process E) the first major portion of the nanofilmis completely removed by etching (e.g., in Argon plasma), and thereafterevaporating the lithium metal layer as described above. In a thirdprocess (Process F), the second major surface of the nanofilm is removedby the Argon plasma etch, and followed by the lithium metal evaporationoperation. In a fourth process not shown, the Argon plasma etch isconfigured to remove both the first and the second major portion of thenanofilm. In some embodiments, rather than completely removing thesecond major portion and/or the first major portion of the nanofilm,those portions are only partially removed to enhance the mobility of Liions. By incorporating operations to remove the nanofilm portion,entirely or partially, the nanofilm can be configured with a filmthickness that is greater than that which would allow facile mobility ofLi ions. For instance, in some embodiments, the thickness of the firstand/or second major portion of the nanofilm is greater than 10 nm orgreater than 20 nm, and therewith provides excellent moisture barrierproperties, and during formation of the solid-state laminate thenanofilm thickness is reduced or removed by Argon plasma etchingimmediately prior to evaporating lithium metal and/or incorporating thesolid electrolyte structure into a battery cell. In some embodiments,after removing the nanofilm first major portion a layer of lithiumnitride (e.g., Li₃N) or lithium phosphide (Li₃P), preferably dense, maybe deposited (e.g., via ALD) onto the glass sheet first major surface toprovide low resistance interface between the sulfide glass sheet and thelithium metal layer.

In accordance with various embodiments of a laminate electrode assemblyof the present disclosure, the assembly includes a solid electrolyteinterphase (SEI) sandwiched between a lithium metal layer and a sulfidesolid electrolyte sheet (e.g., a lithium ion conducting sulfide glasssheet).

In various embodiments, the SEI layer comprises lithium and one or moreof phosphorous and nitrogen. In accordance with the present disclosure,a method of making the assembly, and in particular the SEI, involvesinjecting phosphorous and/or nitrogen into the sulfide glass sheetsurface followed by lithium metal evaporation. In one embodiment theinjecting operation involves implanting phosphorous and/or nitrogen intothe surface of the glass, thus forming an implanted zone; for example,by ion implantation of nitrogen and/or phosphorous using a nitrogenand/or phosphorous ion gun. During lithium metal evaporation at least aportion of the evaporated lithium reacts with the injected surface(i.e., the implanted zone) of the sulfide glass to form the SEI. Theimplantation may be performed uniformly over the entire glass surface(i.e., the implanted zone is uniform) such that the SEI formed as aresult of Li evaporation is continuous layer disposed between a lithiummetal layer of the assembly and the sulfide glass sheet. Uniform may beunderstood with respect to thickness, so the implanted zone thickness isconsidered uniform if the variation in implant thickness (depth) is lessthan about 30%, for example less than 20%. In various embodiments, theuniform SEI may be a continuous layer of lithium nitride, lithiumphosphide or a combination thereof. In various embodiments, the processinvolves nitriding and/or phosphiding the surface of the sulfide glasssheet followed by evaporating a lithium metal layer to form a sandwichstructure composed of lithium ion conducting sulfide solid electrolytesheet, a lithium metal layer, and a continuous SEI of a lithium nitrideor lithium phosphide layer compound disposed there between. In variousembodiments phosphiding and/or nitriding of the sulfide glass surfacemay be performed by ion implantation. In other embodiments the surfacemay be treated with a nitrogen and/or phosphorous plasma followed by Limetal evaporation. The SEI formed as such allows facile electricalmigration of lithium ions between the metal layer and the sulfide solidelectrolyte (e.g., glass sheet). In various embodiments the nitriding orphosphiding operation is performed by use of a nitrogen and/orphosphorous plasma (e.g., via plasma immersion), or by ion implantation(i.e., with nitrogen and/or phosphorous ions directed into the glasssurface using a localized nitrogen or phosphorous ion gun as thesource).

Li₃N is a compound that is highly conductive to lithium ions andcompletely reduced, and therefore chemically compatible in contact withlithium metal; likewise Li₃P. Accordingly, for some embodiments, it isdesirable to achieve a lithium nitride layer compound stoichiometry thatis close to that of Li₃N, and to limit the incorporation of constituentelements from the glass, especially sulfur. To achieve a stoichiometricLi₃N layer, the method of nitriding can involve saturating the glasssurface with nitrogen ions (i.e., performing the nitriding operation foran amount of time sufficient to achieve saturation) followed by lithiummetal evaporation. This method may also be applied for phosphiding thesulfide glass to form a near stoichiometric Li₃P layer compound bysaturating the glass surface with ion implanted phosphorous. In otherphosphiding/nitriding embodiments, it is preferred to allow theincorporation of constituent elements from the glass when forming thelithium phosphorous/nitride SEI layer (e.g., to form lithium phosphoroussulfide compounds) by controlling the concentration and depth of thephosphorous ion and/or nitrogen ion implantation zone.

In a particular embodiment the nitriding/phosphiding ornitrogen/phosphorous injection operation and the lithium metalevaporation operation are performed consecutively (i.e., notsimultaneously), wherein the nitriding, for example, of the surface isperformed first and this is followed by lithium metal evaporationoperation. In other embodiments the nitrogen injection (or the nitridingoperation, for example) and the lithium evaporation operation areperformed simultaneously, or performed partially simultaneously, whichis to mean that the injection operation may be started first and thenevaporating lithium while the injection operation is taking place, andthen the injection operation is stopped while the lithium evaporationoperation is allowed to continue. For instance, the method including: i)a first operation of injecting nitrogen/phosphorous into the glasssurface prior to lithium evaporation (e.g., via ion implantation); ii) asecond operation of simultaneously injecting nitrogen/phosphorous andevaporating lithium metal; and iii) a third operation of evaporatinglithium metal in the absence of an injection operation. Accordingly, theprocess leads to a thin lithium metal layer on the surface of the SEIlayer.

In a particular embodiment the nitriding/phosphiding operation isperformed using a localized nitrogen/phosphorous ion source such as anitrogen/phosphorous ion gun. In various embodiments the ion-implantedzone as defined by the depth of nitriding/phosphiding, is shallow andnot greater than 10 nm. In other embodiments the depth of nitriding isbetween 10 nm to 100 nm, or between 100 nm to 1000 nm, or between 1 umto 5 um. The nitrogen and/or phosphorous containing SEI layer is formedby the chemical reaction that takes place as a result of the subsequentand/or simultaneous evaporation of lithium metal onto the surface of theion-implanted glass surface. The lithium nitride/phosphide layercompound so formed may include additional elemental constituents of thesulfide glass substrate, including sulfur and/or boron, silicon andphosphorous when present in the sulfide glass. In various embodiments,the evaporated lithium metal layer on the surface of the glass is thin(e.g., less than 10 um thick or less than 5 um thick).

With reference to FIG. 9, laminate electrode assembly 700, which may beformed as described above, includes second major surface 201 ii of thesulfide glass, and which may be highly sensitive to moisture.Accordingly, in various embodiments, after laminate electrode assembly700 has been formed it may be stored in cartridge 900, as shown in FIG.9. Cartridge 900 containing a bath of super dry hydrocarbon protectiveliquid 902 and laminate assembly 700 immersed in the bath, and by thisexpedient preserving the sulfide glass second major surface. Cartridge900 is suitable for storing laminate electrode assembly 700 overextended time periods, including hours, days, or even weeks. Moregenerally, the laminate electrode assemblies described herein, and inparticular with reference to FIGS. 8B-D may also be stored in cartridge900, as described above with reference to FIG. 9.

Battery Cells

With reference to FIG. 10 there is illustrated battery cell 1000composed of fully solid-state laminate electrode assembly 700 combinedwith positive electrode 1030, such as a lithium ion intercalatingmaterial electrode (e.g., intercalating transition metal oxides), andbattery electrolyte 1010, disposed between the second major surface ofsulfide glass layer 201 and positive electrode 1010. In variousembodiments it is contemplated that the battery cell is fullysolid-state. In some fully solid-state battery embodiments, it iscontemplated that the positive electrode is disposed in direct contactwith the sulfide glass second major surface, in the absence of batteryelectrolyte layer 1010. In other embodiments, battery cell 1000 may be aliquid or gel electrolyte battery wherein electrolyte layer 1010 is aliquid electrolyte impregnated porous polymer membrane and/or a gelelectrolyte layer. The method of making the battery cell may includeproviding the solid-state laminate electrode assembly and disposing itin a battery cell housing adjacent to a liquid electrolyte impregnatedin a Celgard-like porous polymer layer, and placing the positiveelectrode adjacent to it.

With reference to FIG. 11 there is illustrated battery cell 1100composed of positive electrode 1105 and solid-state lithium laminateelectrode assembly 800D as described above in accordance with variousembodiments of the present disclosure.

In various embodiments positive electrode 1105 is a lithiumion-intercalating electrode. Particularly suitable lithium ionintercalation compounds include, for example, intercalating transitionmetal oxides such as lithium cobalt oxides, lithium manganese oxides,lithium nickel oxides, lithium nickel manganese cobalt oxides, lithiumnickel cobalt aluminum oxides (e.g., LiCoO₂, LiMn₂O₄, LiNiO,LiNi_(0.33)Mn_(0.33)Co_(0.330)O₂, LiNi_(0.8)Co_(0.15)Al_(0.05)O₂ and thelike) or intercalating transition metal phosphates and sulfates (e.g.,LiFePO₄, Li₃V₂(PO₄)₃, LiCoPO₄, LiMnPO₄, and LiFeSO₄) or others (e.g.,LiFeSO₄F and LiVPO₄F), as well as high voltage intercalating materialscapable of achieving operating cell voltages versus lithium metal inexcess of 4.5 Volts, including LiNiPO₄, LiCoPO₄, LiMn_(1.5)Ni_(0.5)O₄,and Li₃V₂(PO₄)₃. In some embodiments the intercalating material (e.g.,an oxide), is unlithiated prior to incorporation in a battery cell, suchas vanadium oxides and manganese oxides, including V₂O₅ and V₆O₁₃.

In some embodiments, battery cell 1100 further comprises a non-aqueouselectrolyte layer (not shown), which may be a liquid electrolyte layerimpregnated in a microporous polymer separator or a gel electrolytelayer or a solid polymer electrolyte layer disposed between laminateelectrode assembly 800D and positive electrode 1105. In otherembodiments, positive electrode 1105 directly contacts laminateelectrode assembly 800D, and, in particular, directly contacts theinorganic encapsulating nanofilm, which, in such embodiments, isconfigured with a material composition having oxidative stability indirect contact with the cathode electroactive material (e.g., thenanofilm surface in contact with the cathode is composed of one or moreof aluminum oxide, zirconium oxide or niobium oxide). Accordingly, invarious embodiments the nanofilm is chemically compatible in directcontact with cathode electroactive material having an electrochemicalpotential versus lithium metal that is at least 3 Volts, or at least3.5V, and the presence of the nanofilm provides a material barrier thatprevents oxidation of the sulfide glass sheet by the cathodeelectroactive material.

In other embodiments it is contemplated that the battery cell is fullysolid-state, and thus devoid of liquid electrolyte. For instance, invarious solid-state battery embodiments, positive electrode 1105 (e.g.,a lithium ion cathode of an intercalation material) directly contactsthe encapsulating nanofilm.

Conclusion

It is understood that the examples and embodiments described herein arefor illustrative purposes only and that various modifications or changesin light thereof will be suggested to persons skilled in the art.Although various details have been omitted for clarity's sake, variousdesign alternatives may be implemented. Therefore, the present examplesare to be considered as illustrative and not restrictive, and thedisclosure is not to be limited to the details given herein, but may bemodified within the scope of the appended claims. For instance, invarious embodiments when referring to nanofilm encapsulated solidelectrolyte structures, the moisture sensitive sulfide solid electrolytesheet is generally embodied as a sulfide glass. However, in alternativeembodiments the sulfide based solid electrolyte sheet may be a sulfidepowder compact composed of highly conductive sulfide polycrystallinematerials and/or glass ceramics or a sulfide glass sheet that has beencrystallized, or partially crystallized to form a sulfide glass ceramicsheet.

What is claimed:
 1. A method for making a solid-state laminate electrodeassembly, the method comprising: i) providing a lithium ion conductingsulfide glass substrate, the substrate comprising a sulfide glass solidelectrolyte sheet having room temperature Li ion conductivity of atleast 10⁻⁵ S/cm, the sulfide glass substrate having first and secondmajor surfaces; ii) injecting nitrogen and/or phosphorous into the firstsurface of the sulfide glass substrate, wherein the nitrogen and/orphosphorous penetrates the glass surface forming an implanted zone; andiii) evaporating lithium metal onto the implanted zone of the sulfideglass substrate; wherein at least a portion of the evaporated lithiumreacts with the injected nitrogen and/or phosphorous to form a solidelectrolyte interphase (SEI) layer comprising lithium and one or both ofnitrogen and phosphorous.
 2. The method of claim 1, wherein theimplanted zone is substantially uniform and the SEI layer is continuous.3. The method of claim 1, wherein the SEI comprises lithium nitride. 4.The method of claim 1, wherein the SEI comprises lithium phosphide. 5.The method of claim 1, wherein the SEI is a continuous layer of alithium nitride and/or lithium phosphide compound.
 6. The method ofclaim 1, wherein the injecting is performed by ion implantation using anitrogen and/or phosphorous ion gun.
 7. The method of claim 1, whereinthe nitrogen and/or phosphorous ion implantation zone is not greaterthan 10 nm deep.
 8. The method of claim 1, wherein the nitrogen and/orphosphorous ion implantation zone is not greater than 10-100 nm deep. 9.The method of claim 1, wherein the nitrogen and/or phosphorous ionimplantation zone is not greater than 100-1000 nm deep.
 10. The methodof claim 1, wherein the injecting and the lithium evaporation takesplace simultaneously.
 11. The method of claim 10, comprising injectingnitrogen and/or phosphorous onto the glass surface prior to lithiumevaporation; simultaneously injecting and evaporating lithium metal;and, stopping the nitrogen injection while continuing the evaporation.